For some demographic reports, notably ring studies, I've used Easy Analytic Software Inc. (EASI). Registration is required but it's free. Ring studies based on the 2000 Census are free, and you can pay for more up-to-date (2004) data. The correct longitude and latitude for the address is required, but the database can provide that. There are also maps and other features that I haven't used much.
But, in testing the site for this post, I've found that, while the longitude and latitude pops up quickly, an actual report doesn't get created. Instead, the page times out. Anyone else using this product?