Always and I mean always double check to see when your passport expires. Certain countries have very strict rules about granting entry into their country if your passport is expired or about to expire.
If you are planning an international trip and have less than 6 months before your passport expires, it would be safe to say you should get that renewed. Keep in mind that renewing your passport normally take 4- 6 weeks, 3 weeks if you expedite it and 8 days if you expedite it at an agency* (based on need only).
For more information on passports and renewals, visit US Passports and International Travel.