Specifically this one:

http://www.totalwar.org/Downloads/Up.../pbmupload.php

I started uploading a save for the BC hotseat, then read a few posts in other tabs. When I went back to that first tab it was at some oddball looking advertisement for that garbageware app. Trying to close that tab caused IE7 to error out, and in the meantime that app had installed itself. It changed a couple of things, installed two .exes with random characters for names ending in elfe.exe.

I deleted them by hand and ran Spybot, which gave me an all clear. So not something really nasty, just an annoyance.