I work a lot with people relocating from other states. Often these folks are referred to me by an agent they use in their respective town. But all too often buyers, and even sellers will choose an agent who they are unfamiliar with in an unfamiliar area. This is where I, or your agent can come in handy for you.
We as agents are constantly networking with each other, either via sites like Active Rain, or industry releated conventions and events. So we probably know of a good agent in your area or the area you're headed to who can assist you.
So if you're relocating, or needing to sell a home in another state, contact your trusted Realtor first to see if they can help you find an agent they know and trust.