Bicycle Mechanics - Squeaking when pedaling

Hello. I just recently bought a 2004 Cannondale r800. I love riding it, but a realy annoying problem has developed. After about 5 or 10 minutes of riding, a realy annoying squeak can be heard only while pedaling. Its almost a chirping sound. Its not very loud. When I first heard it, I initially thought it was a chirping bird off in the distance, if that gives you any idea of the sound and volume. Its definetly somthing in the driveliene. As I pedal faster, it becomes higher in frequency, and as i pedal slower, it slows down. When I'm not pedaling, its gone. Its not my pedals as they spin, I have ruled that out. I oiled the bearings in the rear derailer to no avail, and the same with the bottom bracket(although I beleive its sealed, correct?). The noise realy sounds as if its comming from the crank/bottom bracket area. Anyone care to point out some things I can check?

I always try the easy things first: Grease the pedal threads, retorque cranks, retorque chainring bolts.

A lot of the 2004 cannondales didn't have much grease in the bottom bracket. You'll need to pull it out and re-grease the threads, and that should take care of it.

Is your chain lubricated? This sounds like a simplistic question, but (in my experience) chains are the most likely source of all "squeaking" sounds.

Squeaks could be hard to track down, since sound is transmitted thru the frame. I've had a squeak that sounded like the cranks/bottom bracket. It had all the symptoms - only squeaked when pedaling. After removing the pedals/crank/bottom bracket, cleaning, lubing and reassembling, it still squeaked, exactly the same as before.

It turn out it was the seat post. I removed it, cleaned it and regreased the seat post and the noise went away. I assume when I pedaled, my weight was shifting on the seat/seatpost and therein lies the problem.

Basically, check the seat post and stem/handlebar.

Is your chain lubricated? This sounds like a simplistic question, but (in my experience) chains are the most likely source of all "squeaking" sounds.

Ditto. After a good rain or something, if I forget to relube my chain, it sometimes sounds like I'm making bird calls. Grab your lube of choice and make sure that chain is clean and well lubed! If it's not that, then perhaps it is indeed time to start pulling stuff apart.