A professional should have professional face, professional voice and professional smile. Of course, if you have some professional capabilities, they might help too.
This page centralizes code samples for URL schemes available in many iPhone applications, not only in Apple’s but in many others. It also includes programming tips and references about implementing apps registering or consuming URL schemes.
If you own an iPhone app, contact akosma software to add the schemes you’ve implemented in your application, for others to use. The important thing is to showcase code samples, ready for others to use.