You'll probably have to use the mobile ip. Open a terminal and run "/sbin/ifconfig phonet0", look at the line that starts with inet addr to get the ip. (I'm sure there's a graphical way to check this as well, somewhere in the connection info, but I don't have a device to look up the actual way to see it here). Now your work might also block outgoing VNC in which case you are stuck anyway.

Oh, and there's a "thanks" button next to the reply ones at the bottom of a post that can be used for helpful stuff