change the rdesktop color bit
 

Ummm...
When I try to open a window from rdesktop, it gives me a crappy color bit.
It is like 8 bits. How to give the full performance of the display?

Thanks

Make sure you're using version 1.3.0 or above, older versions don't support rdp5 therefore cannot go higher than 8bit color. You change change the depth with the "-a" option, eg.
IIRC 24 bit only works on windows 2003 terminal servers