"But I only know VB and assembly. "

You make it sound like a limitation !!

I am in the same boat and in the past few years, have never felt the need to learn more languages.

I am kind of confused at your requirement - you said things are fine with keypad+LCD . So where does this PC front end come in ? Maybe you want to control gadgets from the PC using the telephone link from a remote place ? Just to warn you - there are plenty of safety issues to consider if you plan to do something like this from remote - the coding for safety-issues and real time feedbacks will be "n" times more than the control code.

Raghu