I'm new to Mac and just uploaded some photos and chose Share to have some prints made and now the whole app seems to be locked up, I can't close it, or anything... what now?

SOrry but you actually need to share information other than problems - we can not see yoru or your computer and hoave only what you tell us to work with

What version of iPhoto and of the OS? any error messages? what has recently changed? what exactly are you trying to do? Are you trying to order prints from Apple? export photos to order pritns form somewhere else? What eactly?

You can force quit (aple menu ==> force quit) and try again

LN