If you are using OS Commerce, and require an HST-related update, CO4 Computing (co4.com) have a specific flat rate deal for this service.
On the other hand, if you are using Ubercart, we would be happy to help you with this process!
I just found an interesting article slideshow via Slashdot, on how real-life social graphs work, and why current social media websites don’t do a good job of supporting them – http://www.slideshare.net/padday/the-real-life-social-network-v2.
The gist is that people’s “real life” social networks are highly faceted in nature, and the resulting online interactions can be jarring. There’s some food for thought here.