I got my chimney cleaned last year for the first time since I've owned it. I live in a home built in the 60s and I wouldn't be surprised if it had never been cleaned before. You wouldn't believe the crap that came out of there. There were two bird skeletons (just bones)... gross!
Call around and get a good price. Just look in the yellow pages. There are a handful of guys that clean chimneys full time. I paid 100 and my chimney is pretty tall (about 3 stories).