Explorer options

I'm not sure where this question goes, nor if it's doable. Anyway...

In (windows) explorer you can right-click and get a few options (duh!). I've noticed that some programs have put their own options in there (one example is SVN - Tortoise, if you want to create repositories etc...). Anyway, how do you do this?

What I want to do is add an option to open up a terminal window and automatically change to the folder from where it was opened. Normally you start at the root (C: ) and go to the desired folder manually (CD), but since the windows terminal is no where as good as a unix one it can get tedious.

Would this be possible?

New explorer menu items are added from the registry or by shell extensions. Here are details for creating a command prompt from here menu item.