Truly your best source is Craigslist.org. Rental listings that are inputted into the MLS system and that Realtors represent usually are long term (>1 year) and there are very few of them in the local MLS as it is. Most landlords post their ads on Craigslist themselves since it is very easy.
Otherwise, you can look at the Oak Creek Apts. near the Staford Shopping Center. They do short term rentals.