Try to forgive Lundberg - he tends to prod.
Spud, the answer to your originally posted question was given in the first paragraph of post 16. The differences you're seeing are to be expected.
The reason you're seeing different color in different places is that some of your applications are color-managed, some are partially color-managed, and some are not color-managed at all.
If your monitor is properly calibrated and profiled, trust what you're seeing in Photoshop.
Publish your web images in the sRGB IEC61966-2.1 color space and with an embedded profile. That's likely to get your documents seen in the best possible light overall by most people. Whether this will remain the best advice into the future isn't certain.
Currently all web browsers have some problems with color-management, though Firefox is probably closest to ideal after one advanced tweak to its settings is made (about:config, gfx.color_management.mode set to 1). Most of the world doesn't care about color-management, as long as red things come out vaguely reddish or eye-burning red, blue things bluish, etc. Unfortunately, it's getting worse, as portable electronic devices seem to be going the way of ignoring color-management entirely.
-Noel
