You could always use a PIC microcontroller. In my view, a PIC16F84 would be ideal. You would need to invest in a PIC programmer, but well worth it.
If you're not sure what PIC is, do some research on the web.
Basically, you can program a 16F84 to accept RS232 (serial port) commands and produce an output, ie.: drive motors, relays etc.
If you're not big on programming, C++ is probably a bit scary. I would stick to your first idea of using VB. There are also plenty of OCX's out there that can handle video.
You can use SERSEN04.DLL in VB to send commands directly to the PIC via your serial port. See
**broken link removed** for a simple example app that sends characters down the serial port.
Heres a simular project
http://www.rentron.com/PIC16F84.htm
Hope this is helpful,
Dan