You might want to search for phrases, like "free stock images people," etc.
Only source that comes to my mind would be MicroSoft's Office Clip Art/Stock Photos. While mostly clip art, there are also stock images on the MS Web site, along with some WAV sound files.
Others might have some URL's for you.
If you wanted music, or SFX files, I have a list of many sources, and many are royalty free - just do not know about stock images of people.
Thank you for the link, I will look through it.
I know that with Google you can look for royalty free images and also with Flickr.
Flickr has quite a few good images for my project but, while each of them are royalty free, they want links back to them and/or mention somewhere of the original photographer. I have no place to put that on a collage as the list would be quite long...
Check out wikipedia, they have a site dedicated to common licensing. I don't know if they have any people, but it wouldn't hurt to check them out. If you can't find the link, let me know.