PhotoSpills - Easy to use PC collage software with unlimited design possibilities.
PhotoDemon - Lightweight portable BSD licensed photo editor for Windows focused on performance and usability.
Shape Collage - Shape Collage is a photo collage maker software program. Automatically create picture collages in a variety of shapes with just a few mouse clicks. Available for Windows, Mac OS X, and Linux.
PixBuilder - Free Photo Editing Software for PC
PhotoCollage - PhotoCollage allows you to create photo collage posters from a list of photographs.
PhotoFlare - Quick, simple but powerful Cross Platform image editor.