I've got a little (tiny) bit of experience writing programs and I think it would be fun to try to write some apps for the ipad... but I have no money. What is the cheapest possible way to do this? Specifically what is the oldest mac capable of running the software neccessary to write apps? I could afford a really old macbook on eBay but I'm not that familiar with macs so I don't know if one from 1999 will work.