After weeks for trying and testing different software programs I remained unsuccessful, as the mosaics I was creating just didn't look that great. I decided to turn to the "experts" and would select several mosaic companies to create my mosaic.  After extensive Google and Yahoo searches, I decided to review companies that offered some sort of online ordering and pricing. The companies that I found and ultimately reviewed are the following:

Picture Mosaics
Big Mosaics
Design A Mosaic
Mosaically

All claim to offer a superior product, however many fall short of this claim.
Hopefully you find my review helpful and if you have used any of these services please feel free to add your own review or commentary.

A good place to start is the Mosaic 101 page, which describes some of the things to watch out for when creating your own mosaic.

You may also read more about the review process here: The Review Process