There is no block comment in VB.NET.
You need to use a ‘ in front of every line you want to comment out.
In Visual Studio you can use the keyboard shortcuts that will comment/uncomment the selected lines for you:
Ctrl + K, C to comment
Ctrl + K, U to uncomment
There’s not a way as of 11/2012, HOWEVER
Highlight Text (In visual Studio.net)
ctrl + k + c, ctrl + k + u
Will comment / uncomment, respectively