problem with controlling 8 servos

hi everyone i have a problem.. i hooked up 8 mirco servos to the arduino duemilanove.. im able to control them fine but they seemed to be especially jittery.. sometimes when i send a command to move a particular servo the rest of the servos seemed to be affected as well and start to spasm like nuts.. wads happening and how can i fix it?

Have you wired a separate power supply for the servos?
Did you remember to common the grounds?

the servos have a common ground and draw power from the usb connected to the com.. is that the problem?

draw power from the usb connected to the com.. is that the problem?

Oh yes!
You need to provide a supply capable of at least 100mA per servo.

See also http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1240516960