Be specific about the loan you want. The more precise you are, the easier it will be for a loan officer or mortgage broker to find the best rate. For example, do you want a 15-year or 30-year mortgage? Do you need a "jumbo" mortgage (more than $333,700)? Are you willing to pay points to reduce the interest rate? The answers to these questions will depend on several factors, including when you plan to sell the house and how soon you want to retire your debt. Only you know the answers, but the sooner you know them, the better.
If you know that you will be moving in 3 to 5 years, you might want to consider refinancing to a 3 or 5 year ARM (adjustable rate mortgage). These loans typically have a much lower rate that a traditional fixed rate loan such as a 30 year fixed, but they do have a fixed rate for the first 3 or 5 years of the loan. This will enable you to benefit from the lower rate, but you won't ever have to worry about the risk of a rate adjustment because you will be selling the home before the fixed-rate period ends.
Before you refinance a loan, make sure that you carefully analyze any fees that your lender is including on the loan. The Department of Housing and Urban Development can provide you with a list of standard fees. Use it to make sure that your lender isn't tacking on anything extravagant. And by all means, compare their fees with other lenders in the market.
Be Realistic. Lenders have tightened up loan requirements, so you'll need a good credit score and at least some equity in your home to refinance. To figure out how much equity you have, subtract the total amount that you owe on all of your existing mortgages from how much you think your home is worth. If your credit is severely impaired or you owe more than the value of your home, you probably won't be able to refinance right now.