I have used the linked company above and it worked out great. You will have to do some running around, e.g. passport photo to the post office to fill out paperwork etc. all in all pretty painless did the legwork on a Friday and got via fed ex the next day.
also you might want to try www.passportvisaexpress.com. i used them recently to get a china visa in a hurry and was very satisfied. they came recommended from several people at my old company.
Just go to your local passport agency. You might not have one close by. But if you do they can expedite it ($$) and you can have it the same day (if you go in the morning). At least that's true with renewals.