I was at the Security Summit yesterday (based on the DevDays stuff in America), and was reminded yet again of the great Application Blocks that are available, so here's some links:
Microsoft patterns and practices for Application Architecture and Design (the main page)
Some of the Application Blocks that aren't as applicable for me, but here for reference:
Quite a few great bits of code there.
PS: I will be posting an update to my Heirarchial XML into SQL article, as well as it's companion article (SQL->XML), hopefully later this week