Quickly write protecting disk volume in Windows
Starting Windows XP, there seems to be a promising feature of having arbitrary volumes to be write protected. However, there aren't any free or easy to use tool that is available towards making use of this feature. Joeware has released a free tool towards filling this gap. The tool is a small commandline and is available for a free download after you enter your email address (optional) on his website over here.
I think, this should be a very good tool for Windows administrators to add to their routine debugging toolbox.