I've been tasked with managing a project which would see us build a product review site in which customers would be able to leave reviews on websites and the products they buy from them.

This would be similar in vain to many of the product review sites out here such as reevoo.com and epinions.com
Question is this: does anyone know of any software (open source or otherwise) which could host and manage the product reviews for multiple products over multiple sites?

Iíve had a good look in various places and canít seem to find anything.

Any help and suggestions would be greatly appreciated.