How do I get the return codes after using shell?

Basically, I'm establishing a secure tunnel via Cisco VPN Client and appending all command line information to a log file. I think that I'm fine with that (I've searched through the posts here and have found some great info). The other thing that I need to do is react to the return codes.

How do I view errorlevel in VB. Do I shell(errorlevel) or what?

Any thoughts will be appreciated.