My dad would like to buy my old Macbook off of me and use it to create iPad / iPhone apps. My Macbook is Intel Core Duo (not 2), so I cannot upgrade to Lion (unless someone knows how). I currently have Xcode v3 loaded since without Lion I cannot load v4. Will this constrain my dad from creating apps for the newest iPhones / iPads? He's worried that for example, he may want to create something for the iPhone 4S and he will not be able to because of the older OS. If he would be constrained at all, could you please give me an idea of apps that you would need Xcode 4 / Lion for? He was also wondering if the hard drive can be upgraded, if anyone has information on that. Thanks!