Here are a few tools/apps used to create a collage quickly, easily and efficiently.

• Picasa,
• Cool Iris
• Prezi.com
• linoit.com

These are all great presentation tools but there is bit of a learning curve.   Tutorials for all of the above are offered at the respective sites.

 I have seen Microsoft PowerPoint, the classic software best known for presentations,  used with limited potential to create photo displays.
There are other solutions. For example, a copy of Microsoft Auto Collage – it’s very easy to use and very intuitive.  The retail price is about $20.00 US
Here is a link for more options

 http://maketecheasier.com/5-free-tools-to-create-collages-from-your-pictures/2010/02/23.

If you know of other solutions, please let me know via this blog or through Twitter.