As a practicing podiatrist for almost 3 years, I think I can give you some useful information.
First, I would recommend stopping by the Podiatry Forum (look under google.com for "podiatry forum") There are a lot of posts related to income, etc.
No matter what residency you do, you're unlikely to make much more than 50k in your first few years. Jobs for MD's and DO's are more plentiful and organized. There are very few attractive associate positions open to someone who just finished their residency. Most of them will come from a podiatrist who is looking for someone to work a nursing home cutting nails or doing some other unglamorous duty. In other words, don't be expected to be "hired" by some hospital or medical group when you're finished with your residency. I finished mine in 1999 and I'm still at the same clinic slogging away at nails and calluses. My cohorts, who had more surgical training than me, are doing the same thing.
Podiatrists also get reimbursed less than MD's and DO's for their services. Oftentimes, they get even less than other health practitioners such as nurses, PA's and PT's. It's embarassing.
As far as starting your own practice, you're going to need to take out yet another loan (if a bank will allow it taking into consideration your likely $175,000 school loan debt and the outlook on your future earnings) in the range of something like $50-100,000. And then there is the additional constraint of getting on health plans to actually see patients. It is required by the majority of insurance carriers that you be board certified in podiatric surgery before they'll let you see their patients. When I was a student, that kind of training went to less than half of the graduating class leaving the rest of us a one year, non-surgically based "residency", which left many with few options. These days, there is practically NO competition to get into podiatry school, thus, whatever surgical residencies that do exist will have a smaller applicant pool to pick from. Your chances of being surgically trained are greater, but....you should really check out the podiatry forum.
You need to keep in mind that unless you've socked away $175,000 or so to fund your education, you're going to be required to begin paying those loans off when you finish residency. I don't know where you're planning to live or practice, but just by doing some simple math, it should be evident that $50,000 doesn't really go a long way. Especially if you're considering taking out even more loans to start your own practice.
Give it some serious thought.
