For windows XP be sure to have nothing in color management window, if you find one just delete it.
For vista and OSX just have the best monitor profile, there are many calibration apps, ((OSX has its own, but its best to use a monitor profile that came with your mac, (24'' imac, or 24'' led display). For other fine monitors just use calibrator))
Older macs as my 2.33 dualcore 17'' mac book pro, work better with sRGB.
Here comes photoshop. First go to edit>color settings and on working space assign your monitor profile, tell photoshop not to color manage anything on import. Something very similar works with gimp.
When you PP an image, just convert it to a common color profile like sRGB -please dont assign your monitor profile because possibly you are the only one on the planet who has it.
If you don't want to do all these, just use view>proof setup and have a look how typical windows or macs or your monitor profile looks like.
Sorry for my english, I hope all this above helps.
Remind you this too. Lots of users use windows XP. Just a few can see colors correctly. Colors on my PC look the same as on my MACs. Give a try and don't be suspicious with mac users.
Again: Vista and OSX have a fine color management, XP or some Linux have not.
*here's a test. Download one of solo's fine renders, open in photoshop, assign sRGB profile, save, quite. Now open in preview and compare this with explorers's or firefox or safari's site view.
No I have a better idea, see solo's render with sRGB assigned. Compare it with the attachments preview (SCF machine discards color profiles when it creates previews)