Looking for posters of HST Images ?
Spaceshots sells the famous Hubble M16 Eagle Nebula image for $10.95 in a 16'' by 20'' size (laminatation or a frame is available for extra cost). And a host of other images, including a new series called Hubble's Universe.

Sky Publishing the publishers of Sky & Telescope Magazine also sell the same image, called Starbirth In Serpens for $9.95 in a 36'' by 24'' inches. They also have a Deep Field poster and HST image slide sets.

Questions about using HST images and copyright information ?
look here for copright information from the Space Telescope Science Insitute.