another problem people seem to do when they are told to close the face a bit at setup, is setup the club then rotate the club shut. make sure you do not do that, you should rotate the face a bit closed, then grip it. proper grip is also key, make sure your "Vs" are lined up as well. try to maybe keep you left arm more conected to your body...hold a glive in your armpit and make a swing without having the glove fall to help you stay more connected. maybe try to relax your hands/arms more, being too tight might prevent you from releasing properly too.

this drill is also geniuos form our very own greg

http://members.cox.net/gregjwillis/LESSON1.htm

i think every amateur should see this website, it would probly cure a ton of accuracy and power problems on its own.

just some of the things i can think of that would help fix a slice, hope one of them helps.