How can I determine the demand for homes to rent in a area.  I am concerned with the question, if I fix it up, will I be able to rent it?

I have found the best way is to contact Realtors and other investors in the area.

id take a peek at MLS rentals in the zip and see how old the similar #bed/bath or sq ft house for rent listings that havent rented yet are (extra step to be sure would be to call to see if those that appear sitting unrented really still avail as alot of listers are sloppy and never update once vacancy filled).

Look at comparable inventory, if inventory is high, demand is low, I inventory is low, demand is high. Look at the average income for the area, tenants can get in at 33 to 40% of gross income, what would be the mean price range? Does the inventory support that population? Then work to bot sides of the mean, keep in mind the population at different income levels and compare inventory accordingly.

Or, you can call property managers and ask how long it would take them to fill your unit.

Or, if it's at the lower end of the spectrum, call the housing authority or section 8 office and ask them how the demand is moving.

And, look at the MLS, you can see hotter areas and price ranges, properties that are selling are usually easier to rent too. Good luck :)

Thanks for all the advice.

Craigslist is a good resource for seeing what is available for rent in your area and use those as comparables.