Go to your local Wolf or Ritz camera and they should have some sort of lens cleaning liquid. Don't use water, or anything not specifically made for cleaning lenses, as it could damage the front and rear elements or spot up easily. Additionally, you'll want some cloths specifically for lenses so you do not scratch the front or back.
Also pick up a cheap hand-pump blower ($2-5 maybe?) at the camera store and blow the dust off of the lenses first. The front and rear elements can be very sensitive to dust, so you don't want to be rubbing the dust into the glass and wind up having some of the particles being particularly abrasive.
I recommend "Pec Pads" for cleaning lenses - http://www.bhphotovideo.com/bnh/cont...ughType=search
I also keep UV filters on the front of my lenses at all times, that way I'm cleaning a $20-50 filter and not a $1000 lens. I rarely, if ever, touch the rear elements, usually just using the blower to get rid of any stray dust.