I refi my rental property before I officially had moved out. I went through the VA though. I went with a VA Hybrid loan which was pretty unique. I am paying 3.5% now!!!
For those that aren't aware of the VA Hybrid:
http://www.valoans.com/arm.cfm
yes it is an ARM loan but since I started out at 4.5% which was down 1.5% from my original fixed rate. The rate can only change annually and no more than 1%. it also can not rise more than 5% over hte initial rate for the life of the loan. I actually dropped 1% to 3.5% on my first adjustemnt. So even if the rate went up every year for the next 6 years to teh cap of 9.5%, my payments will still be less than if I had paid 6% thorughout the life of the loan.
If any of you have VA access... it's definitely somehting to look into.