I've written up a small program that demonstrates the use of CryptoAPI for creating keys, signing things, and verifying signatures. You can grab it here (http://www.valhallalegends.com/docs/CryptoAPISign.cpp).
Plenty of other documents (http://www.valhallalegends.com/Documents.asp) are available for your general usage on the site.
Now someone just needs to convert that to VB instead of scary C++.
ill do it when i get back from cousins bat mitzvah