(a USGA service)
GHIN is the official handicap program widely recognized by most golf courses and tournaments. It is typically available as part of your membership with the local golf clubs (e.g. men's and ladies' clubs at Hangman Valley, Liberty Lake, and MeadowWood). Fees vary by clubs between $45 and $75/year.
This is a free tool that calculates your handicap based on your scoring history. It is unofficial and you do not get a GHIN Number.
Digital Golf Applications
There are many free and paid mobile device applications available on both Apple and Android platforms that can help you calculate and track your handicap. Simply search for "golf handicap" in the app store.