Aphi:TA, if lauradav hasn't grabbed you already with a PM, go to the Alpha Phi web site, use the form there to make sure that EO has your current contact info, then go fill out the VOLUNTEER INTEREST form! The Human Resources Coordinator for the Southwest will either call you or e-mail you quickly--or both!
I was in the same boat as you a few years ago, having moved from my collegiate chapter in Wisconsin to Kansas, then California. I did exactly what I said above, and here I am going on to my second Chapter Advisory position! Alpha Phi loooovvveeeessss volunteers!