Hi J.,
My husband and I have been licensed foster parents since October through Hennepin County. I think the nuts & bolts vary a little bit from county to county, for example, Hennepin County paid for all of our licensing expenses, and their monthly reimbursement rates start at around $600. Of the reimbursement, we maybe wind up with a little extra each month but out of that money you're expected to cover all of the child's expenses -- clothes, diapers, a bed, a dresser, a car seat, food (though foster kids under 6 are eligible for WIC regardless of your income), gifts, plus the extra gas shuttling them around to appointments (parent visits, the doctor, any therapy, etc). If you like taking care of kids but want some actual extra income, doing in-home day care is probably a better way to go. Speaking of day care, that also needs to come out of the monthly reimbursement if you're working, as the county doesn't pay for it.
The licensing process is extensive and takes about 6 months, so that also gives you and your family lots of time to think things through! It definitely needs to be a whole family decision, because even if you'll be doing the bulk of the parenting during the day, adding a foster child (or children) affects the entire family. They do a lengthy home study and background check, and then there are 21 hours worth of training to attend. We also have a 6-year-old daughter and the county is fine with that, but they do have some rules and recommendations about where foster kids can sleep (opposite genders can't share a room after a certain age, and your kids should be 2 years older than any foster kids who also sleep in their room, etc) so space in your home is a consideration.
The parenting itself is very rewarding and it's easy to forget on a day-to-day basis that the kids won't be part of your family forever. The birth parents' visits can be challenging, and the kids we've had so far have needed more trips to the doctor than our daughter did. The single hardest thing is that, even though you know the kids won't be with you forever, you do fall in love with them and think of them as your own and it's heartbreaking when they leave no matter where they're going, whether it's back to a questionable birth parent or to a relative who seems great. We're in the adoption-option program, but even then only 33% of the kids go on to be adopted by their foster parent and the rest return to birth parents or go to a relative -- adoption by the foster parent is the county's third-place choice. I don't have enough space here to complain about how messed up the system is! If you form a good relationship with the birth parents (who are human and have just made some really, really bad choices and mistakes), though, you may be able to still be a part of the kids' lives afterward. Feel free to send me a private message if you'd like to talk some more -- we found it really helpful to talk with other foster parents beforehand (and still).
Blessings,
Sara