Anybody had any success with this? I'm under the impression google can't crawl the dynamic pages so I might have to make static copies of some pages. Anyone know how to use this script?

Yes, I have used this tool and it works good.

Another method I have used was downloading the product, category and catprodx tables from the database. Then I wrote a php app to display the the information the way I wanted to display it.

In both of these examples, you are basically recreating most of the frontend of the store.

There are also lots of other stores that will run just fine here at WestHost that are free. A popular example is OSCommerce.