Google has been supporting Rich Snippets for a while now. Most recently, they added a more types of markups to add to your HTML in order for Google to provide richer descriptions in the search results.

One of those additions is product data and a WebmasterWorld thread now has discussion around it. There is a lot of technical detail on the Products microformats or RDFa labels at Google.

Here are the fields allowed:

brandcategorydescriptionname (fn)pricephotourl

Forum discussion WebmasterWorld.