I have posed this question to financial aid officers at 3 different schools at my interviews. I am a working-full-time post bac and am filling out my FAFSA based on a 2002 income of around $30,000; not a huge amount of money, but high compared to all those college kids with minimum wage work study jobs.
The answer I've gotten everywhere has been that you put it all on the FAFSA. You will come back with a bigger EFC than the other kids. You will get your package from your schools financial aid office. If you think your ability to pay based on your past year income which is non-existant in the present is over estimated you will go talk directly to the financial aid office. They, being humans rather than a computer performing algorhithims, will actually look at the picture and work with you to figure out what's going on and help configure your package with extra loans (or grants, depending on the school) to cover the gap between how much money the FAFSA thinks you have and the reality that you income is in the past.
So, yes, having an income will affect the goverment's calculations. But the schools will step in to help as necessary. Don't get too excited - at GW they were very plain about the fact that any such shortfall will just mean more loans since they don't give out much grants. But they will actually work with you to put together a package that will let you go to school. At least, that's what they tell me.
