If my company is incorporated in DE,
but I live in CA,
yet I only sell iPhone apps,<p>do I have to pay CA corporate taxes?<p>[Does selling iPhone apps count as doing business i CA?]
As always you should probably seek more authoritative advice, but my understanding is that you'd only pay CA corporate taxes, and <i>not</i> DE corporate taxes. Most states tax corporations on the business they do in the state, and it sounds like you do all your business in CA, so you have to pay CA taxes. But you don't have to pay DE taxes, because DE has a special exemption for DE-registered corporations that do all their business out of the state.
I don't know for sure, but I would guess that you pay corporate taxes where the company is incorporated, and the location of your employees (i.e. you) doesn't matter. That said, it may be that CA law prohibits residents from incorporating as sole-person companies in other states.<p>Are you going to take HN responses as authoritative? I really wouldn't. Go see a professional tax adviser.