I have been getting into designing interfaces for iOS, mostly iPhone and iPhone 4 retina display. I'm wondering how I should go about creating interfaces, the most standard way? I have been using the iPhone 4 GUI PSD which helps a lot. But I'm really interested to create my own buttons, and scale them easily into @2x sizes.
Some great examples of apps that use custom buttons are Instagram, Foursquare, Gowalla, and Tweetbot to name just a few. Ideally I'd like to stick with Photoshop since I'm most comfortable with the tools and layout. I haven't worked with vector graphics a lot, but I'm willing to give it a try if scaling for @2x is easier. But I'd love to hear any advice!