Where to learn to make Facebook apps?

I wanted to see if anyone on here could point me in the right direction for some training on developing facebook apps?

I have been building basic forms and landing pages using iFrames but would like to see how to make apps like the ones found on these pages:

Fanzilla
401social

Be interested to start making some better looking apps that I could sell like these people do, rather than building apps for each individual client

Thanks fellas

start with Adobe Flash or HTML5 (better), and some php programming and you'll be fine