I just used this awesome web site to create my Facebook banner...
Click on create collage
You'll see on the left hand side various little images - the top one is upload photos
Upload any photos you want
The next image is the type of collage you want. In this case *Facebook Header*
Choose FB header from the left hand side
Drag and drop photos into the template on the right hand side of the page
Save and upload...
Took me five minutes at most...
awesome sauce.... 'course I can only see it small on my laptop... hope it looks okay on big screens... ROFL