Looking for a simple collage maker for Mac or PC

I've checked out several of these programs and find them very complicated.

All I want to be able to do is create pages consisting of multiple  
photos arranged into multi-photo layouts.  What do I mean?  Simply, I'd  
like to choose 4 photos (mixed portrait and landscape) and arrange them  
into 2 rows of 2 photos, or 6 photos and arrange them into 2 x 3, or 8  
into 2 x 4, etc.  There would have to be margins large enough to write  
on.

Does someone know of something that would fit this need?

Thanks in advance!