My favorite easy fingerless mitts pattern at the moment is at
http://explaiknit.typepad.com/ - Everybody's Squooshy Mitts (pdf pattern link is in the right-hand column on the blog).
The best thing about this pattern (for me) is that the thumbs are knit first, and attaching them is easier this way. Plus, if I have a limited amount of yarn, I don't have to guess how much to leave for the thumb, and since it's top down I can keep knitting until it's either long enough or I run out of yarn.