If you want to create a collage of your favorite photos and put it on a poster, Posterino 1.1 is the slickest and easiest way to get the job done. The program offers a variety of templates, with grids of identically sized frames or with mixtures of shapes and sizes. Adding photos from iPhoto or elsewhere is a cinch. You can have Posterino fill the frames for you, or you can drag and drop images manually for more control. You can also change the size and shape of individual frames, and adjust the placement of each image within its frame. Export options let you send your finished poster to iPhoto or Flickr, hand it off to your e-mail program, or save it elsewhere on your hard drive.
http://zykloid.com/posterino/