"Do not use any sort of "canned air" for this. It may be too powerful and the types that are liquid driven can "spit" liquid in the gas stream and if that happens you can wave bye-bye to your sensor. They may also freeze the sensor, which again could result in damage."
From -
http://www.photo.net/equipment/digital/sensorcleaning/
I've cleaned my D100 sensor a few times using Eclipse cleaning solution and pec pads. Wasn't all that hard.