Well, I don't know if I'm really that good, after all, I only really elaborate on what Darthatron's tutorial says. If you want I could send you the source to one of my programs, then you can look at it and see what does what! It's usually the best way to understand!
You could always download Visual Basic 6 Portable. Its only about 6MB and is stand alone with all the functions of the 125MB one that you need to install. Try googling it to find a working link. You'll find it eventually...
Well, the best place to start is with Darthatron tutorial in the Toolbox! Try to make his test DP starter program, and see how you get on. By the way, you specifically need Visual Basic 6, as this is what his tutorial uses and the language I code in and "understand" :D
When you have done that find some hex values in a ROM and see if you can change them in the same way. Combo boxes are the easiest way to edit information as you can just convert the listindex into hex and write it back!