I haven't tried this myself, but
here's a bunch of other people who have posed this
question and here's a link to that group..
Theres an ExitProcess method that you can use, but it has some side effects that are discussed here....
http://groups.google.com/groups?as_q=exitprocess&safe=images&ie=UTF-8&oe=UTF-8&as_ugroup=*.vb.*&as_scoring=d&lr=lang_en&num=100&hl=en
hope this gets you started...
Nandan Dharwadker
Staff Software Engineer
Measurement Studio Hardware Team