"...The XML Documentation facility built into all the .NET languages..." - I wish! VB.NET supports intellisense so the hovering images of what something does will be supported if you are looking at something generated in another language. I tried all I could think of to start that facility until I read specifically that it isn't supported in VB.NET.

Yes, it would be nice if that facility was built into SQL as well, however the intellisense currently built into SQL 2008 is 1 out of 10 times helpful and 9 out of 10 clueless, distracting, and throws me off. It's like a 3 year old with no clue of what you are doing trying to be helpful. In other languages, you type "Me." or "this." to tell the system, yes, I expect some help.

That "mind reading" comment made elsewhere belongs with the Microsoft supplied intellisense, which is very apt. And yes, it isn't a full-blown documentation tool, but at least you can get a 1 line reminder of what something is for, at least in your own coding practices.