From the product page, it looks like the API can be used to create auditing capabilities using the transaction log in your own custom application. When I get the time, I'm definitely going to have to delve deeper into it and see what the capabilities are.
On a different note, if you've not come across Paul Randal's sample databases for SQL Server 2000 and 2005, you can find them here, and some testing you can do with them:
I only recently ran across this post, even though it's from September on Paul's SQLSkills blog. Mr. Randal originally posted them to the SQL Server Storage Engine blog when he was still with Microsoft.