You can change most of the colors editing the registry manually.
I posted at my How-to site how to change a few of the items
http://www.tweaks2k2.com/howto/viewt...fa382f79388fe4
All items in Today screen are listed in the registry here:
HKEY_LOCAL_MACHINE\Software\Microsoft\Color
Tweaks2k2 includes options to change all these colors. Including WM5 colors which are a little more complicated to change.