Firefox 3 is now available. one nice thing for photographers is that it’s color managed, it obeys profiles tagged to photos, but this capability needs to be turned on, it’s not on by default.

Mac Safari is a color managed browser. Not sure what else is.

Firefox 3

How to enable color management in firefox 3

see if your browser is color managed and see some great examples of why it matters.

Second page on that topic:

http://www.gballard.net/psd/srgbforwww.html

page from Apple on this topic:

http://support.apple.com/kb/HT2026?viewlocale=en_US