Hey
I have been in Warsaw several times , and I have to say that after Krakow that would be my 2nd favourite polish city.
There are a lot of things that are worth of seeing.
Take a look at these links (all in english !) , they should give you a good idea:
http://free.polbox.pl/p/psbor/ewarszaw.htm
http://www.thevisitor.pl/warszawa.php
You HAVE to go to wilanow palace, palace on the water and old town square, its just beautifull.
If you have any questions you can always PM polish dude
