Why color changes when Save for Web, ImageReady, and or the internet?
The bad color issues generally falls into FOUR PROBLEM AREAS:

1) Photoshop CS3 CS2 PS 10 9 8 7 Working RGB is different from sRGB–type ColorSpace.

THE REASON IS:
Over 90 percent of web browsers strip embedded color profiles, and they apply a Monitor-type RGB to all web color.

The color shift or color change with Adobe RGB (1998) for example: The overall color looks unsaturated desaturated, especially reds, and washed out when Photoshop "Save for the Web" or "Jump To" or "Edit In" ImageReady, and/or when pictures are viewed on internet web browsers like Safari, Explorer, FireFox, OnmiWeb, Opera.

Photoshop CS2, CS3> Edit> Convert To Profile: sRGB IEC61966-2.1 BEFORE Saving for the Web, or going to ImageReady, or posting photos or graphics on the world wide for web browsers. In CS1, PS7 and earlier: Image> Mode> Convert To Profile: sRGB IEC61966-2.1.
NOTE: The monitor will also need to be calibrated-profiled to 2.2 gamma, 6500 degrees Kelvin D65.
If you are on a Mac, I highly recommend you re-calibrate your monitor to 2.2 monitor gamma, D65 6500.
SEE apple.com article: "Color and gamma settings for print and web."

HERE is a look at the new SFW Save For Web Devices settings in Photoshop CS3.
CS3 changed how Photoshop 10 Save For Web works with ICC Profiles so be sure to understand how SFW works. ImageReady no longer exists in Adobe Creative Suite 3. In CS2 and earlier, we always need to manually Convert to sRGB before ImageReady or Saving For Web.

PROOF my point HERE in your color-managed web browser — a side-by-side comparison tutorial of tagged and untagged AppleRGB, sRGB, Adobe RGB (1998).

• NOTE: Apple's Safari web browser is a color-managed web browser for both Apple Mac OSX and Windows Vista and Windows XP operating systems. Read the color-management link for more information, including where to download Safari 3 for Microsoft Windows XP Vista Professional Basic Home platforms.

Photoshop can effectively "SoftProof" our web browser color:

• Photoshop: View> Proof SetUp> Windows RGB
• Photoshop's Soft Proof screen preview here simulates how unmanaged applications, web browsers, will display the file on 2.2 gamma monitors, based on the sRGB profile. If the file is based on sRGB and our monitor gamma is 2.2 and D/65 6500 degrees Kelvin, we should see very little shift here, which is the goal.
  
  
• Photoshop: View> Proof SetUp> Monitor RGB
• THIS IS WHERE the color-brightness-saturation problem will repeat consistantly.
• Soft Proofing Monitor RGB here strips-ignores the embedded ICC profile and Assigns-Assumes-Applies the Monitor profile or color space.
• The color and density changes seen here show the difference between the monitor profile and the source profile sRGB.

Side Rant: sRGB is arguably the current target RGB ColorSpace for internet publishing because the world wide web is not color managed. sRGB (standard Red Green Blue) sRGB is a generic monitor-type profile that tells "average" 2.2 gamma monitors how to display color. There will still be some error between unmanaged sRGB color and accurate calibrated 2.2 gamma monitors, but the difference will likely be acceptable negligible on screen because — unlike AdobeRGB — sRGB is a monitor-type, device-dependent profile. What is Adobe RGB (1998)? On the other hand, Adobe RGB (1998) is a specialized "high-gamut" device-independent ColorSpace for professional use in color-managed applications like Photoshop. The AdobeRGB ColorSpace, ICC Profile, ColorSync Profile has nothing to do with monitors or printers. This is why Adobe RGB displays and prints so bad when the profile is ignored. MY POINT: Adobe RGB (aRGB) is unsuitable for use outside of color-managed applications, and aRGB is the worst popular colorspace to put on the internet.

3) The monitor profile is bad — the shift here — anything can happen when other monitors display the color.

• The reason: The document color was balanced on an inaccurate monitor, bad Monitor RGB.
• The fix is to "calibrate" the monitor Get A Good Screen and correct the color.
• Color Only Looks Bad in Photoshop and other color-managed programs like Apple OS X iPhoto and Preview application.

The reason being, Photoshop Color Management is broken, please see
Turn Color Management On & Honor My Embedded Profile, please gballard.net.
The fix is to set a not–broken workflow (see the following Photoshop sRGB work flow for the web).
Then, if not already in sRGB, Convert to sRGB IEC61966-2.1 before Save for Web, or exporting the color out of Photoshop.
Photoshop ASSIGN V CONVERT to profile tutorial -- don't confuse the two!

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EMBEDDING ICC PROFILES in Creative Suite 3 CS3 Photoshop 10 PS10.

Adobe Photoshop Save For Web Devives "ICC PROFILE" option will embed ICC profiles in web images -- embedding profiles in web photos graphics is not recommended.

HERE is a look at the new SFW Save For Web Devices settings in Photoshop CS3 including SFW Tips Workflows.
Again, Photoshop 10 changed how Save For Web handles Conversions to sRGB so be sure to understand how CS3 has changed and how to prepare color files for the internet for the best possible color in web browsers.

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A Photoshop WorkFlow for the WWW:
Note: WorkingSpace> RGB: sRGB is NOT recommended for pre–press users.
Pre–press and print users should use a high–gamut WorkingSpace> RGB: like AdobeRGB.

Photoshop> ColorSettings (Command+Shift+K on Mac):

The above settings set Photoshop's WorkingRGB — the ColorSpace Photoshop embeds/tags — to sRGB IEC61966-2.1. For more information on these settings, and HOW changing them can break Photoshop, please see: Photoshop's Back Door.gballard.net.

Once we match the settings, Save with a unique name (so you'll know if someone alters it because the name will change to Custom) — simply (re)Load the correct Settings.

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Therefore, it is my opinion that setting RGB Default to 2.2 gamma sRGB ColorSpace — and "calibrating" a 2.2 gamma custom monitor profile — will serve more users better, with less confusion.

In any case, 1.8 Mac gamma is a shifty proposition in a 2.2 gamma PeeCee–Windoze world.

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If your WorkingRGB is Adobe RGB (1998), like mine, or any other Color Space than sRGB, we need to: Photoshop> Image> Mode> Convert To: sRGB IEC61966-2.1 before Saving for The Web, or going to Image Ready, or putting the document on the web.

In other words, we Convert our device–independent, wide–gamut AdobeRGB file to the TargetRGB ColorSpace (sRGB).