VB 2005 Express is free
here. VB 2005 has a very simple serial communication control. When you register VB 2005 you can download an e-book that has some very basic information on VB. Read that book and you should be able to figure how to do this.
If you have any questions PM or e-mail me and I will help you any way I can.
EDIT: I am curious are you referring to the robotic arm from the "Build Your Own Humanoid Robot"? Your drawing looks like the VB6 program from that book.
Hope this helps
Eric Haskins
haskinseric@hotmail.com