I mention this in one of my beginner PC classes, but I just want to reiterate this very important factoid:
Be VERY careful when using labels in LASER printers. They have a tendency to PEEL OFF inside the printer - especially cheap ones (cheap labels and printers).
NEVER EVER EVER use a label sheet more than ONCE through a laser printer. The heat melts and softens the label glue, making it even more prone to come off the second time through!
I just recently had a label peel off inside my color label printer (which is why a bunch of you are getting black & white labels on some of your CDs this month). It took me a WHILE to fix it... and I know how to take these things apart and clean them. If you don't it's a COSTLY repair bill.