Can anyone tell me a website with all the TA downloads?
Depends on what downloads your after :}
www.funthings.org
http://www.unituniverse.com/
that usually does me pretty good. I've gotten some really nice units from there
http://www.d-gun.com/files/maps/
http://www.at-systems.copperstream.co.uk/subedei/maps.html
http://plu.tauniverse.com/maps1.htm
http://www.shonner.com/ta/
http://www.xxx.com/