it's not too hard to swith out...I've done it on an iPod touch. Just be very careful with the ribbon cable, it's very fragile.

http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT

this is what you want, it's the whole digitizer (the glass you cracked which is actually the touch screen) + the frame that holds it in, already put together and everything...all you have to do is pry the other one out, plug this one's cable in and snap it into place.