I do REOs. That's all I do mostly, sometimes private sellers, but mostly REOs.
Seeing that there are tenants in the property, I wouldn't assume the property is in horrible shape, but then again, people sometimes have no choice but to live in not so safe/clean/functional housing. Things to watch out on are what you'd watch out on any property -- all of the major elements of the home, plumbing, electrical, mechanical, foundational/structural, roof issues. Those would likely be the major things.
Foreclosures are usually "as-is" without any disclosures, so, I'd DEFINITELY get an inspection from your inspector--make sure it's thorough and because you're local, you should be there when the inspector's there.
Also, regardless of the price you come in at (even if it is full price), you'll want an additional stipulation in there that says the rents will be pro-rated as of the date of closing and that you'd like to negotiate a lease with the current tenants prior to closing (or even prior to the end of the inspection period). A month to month tenant means they can leave in 30 days (and, if they want, tomorrow--and you have little recourse) and if you have one leaving in October, that's pretty soon. Also, October gets into the colder months which is generally a more difficult time to rent properties. If you can negotiate new leases from say, August 1st, 2010 (I don't know if the bank will allow it), you might really be able to do some good stuff with this deal.
Check and re-check the numbers, but the basic formula for a cash flow property is:
1) Figure out max payment... Market rent - desired cash flow (net income per month you want) - management fees (if any) - maintenance/vacancy reserve = Max payment (PITI)
2) Use this PITI figure in a mortgage calculator and figure out the original loan amount.
3) Figure out offer... MAX OFFER PRICE = Loan amount - Rehab - Holding costs - Closing costs
There are several unknowns, so generally, 50% rule makes you money. So your max all-in should be $55K including closing costs, rehab, & holding costs. Depending on the rehab, this looks like a pretty nice deal.