Do it yourself

I have a sears dryer that is only about a year old. I just had the yearly inspection that sears does and the sears guy told me to have the dryer vent cleaned. The dryer is in the middle of the house and is vented to the outside via a long tube or hose that is approximately 15-18 feet long. How does one go about cleaning this? If it involves going under my house I'll call some one. WHich leads me to question 2: who does one call to clean a dryer vent? Sidney