@pabloruiz55 - Congrats on your success! =)
@jd -
In the US I typically charge around $100-$150 / hour for client iPhone development. I'll go towards the lower end of the scale if I'm getting a percentage of the profits ( typically around 10% in my experience ). That can be discussed with the contract.
Most application development for clients can go fairly quick, in my experience averaging 1-4 week turnaround. This is much smaller than the typical life-cycle for other development projects I get contracts for, so the rate is higher to compensate.
As for which one can be more profitable, it's difficult to say. After a year I can still get at least a couple hundred each month from released stuff, so I think the residual aspect of the income plays pretty large in my equations. I also typically find more enjoyment working on personal projects, even if I don't end up releasing them.
But for me the biggest thing of all is that I enjoy developing, and I like developing for this platform. Because of that, I could make squat off my own apps or even never release them and still not regret it. I haven't made my millions off any of it, nor do I expect to - but that won't discourage me from having fun. =)