from what ive read you only need to clean the barrel every few thousand shots, and maybe never as long as the gun still is accurate ...
When using a cleaning rod, be sure to enter the rod in the breech, because if you happen to damage the muzzle you are screwed ...
About those cleaning pellets, i've read 2, 3 or even with a normal pellet behind the cleaning pellet.
One would definately be too little resistance and you would get a dry fire .
So, if you havent fired that many shots yet, i'd leave the barrel alone as long as accuracy is good .
Do a search for "cleaning barrel" at
http://www.airgunbbs.com or
http://www.airgunforum.net and im sure you'll get loads of information right now
(this forum could really use a search function as well)