http://quantumbooter.net/
this one actually works, that one is used by many kids, and even the one who attacked my server ... :S
the prices are very cheap, and I've bought lowest packet to test it on my 1gbit server, opened ssh, started iftop to check for traffic and see ddos strength, activated ddos using SSYN type, and BOOM, connection time out from my dedi ...
http://www.hackforums.net/forumdisplay.php?fid=232