I live and work in Southwest riverside and the rental market here is great. Along with the rest of Riverside, the Temecula/Murrieta area has dropped significantly in price, however, the population and quality of tenants has remained strong. We are the southernmost point to San Diego, where prices are about double, so many people commute daily. Excellent schools and low crime help keep the neighborhoods renting quickly. Also, so many people have gone through a short sale or foreclosure, that they now have to rent. (Yes, these folks lower credit, but as long as the rest of the credit (utilities, credit cards, etc) shows regular payments, they are still great tenants.) 3-4 bedroom house for around 190-220K, can rent from 1550-1800 per month.
I own several in the area myself and recommend this area highly.