After reading and help from Kota2k2, I cleaned my 350D sensor for the first time.

Using a tripod, fully charged battery, medium Giottoes Rocket-air blower and SensorKlear by lenspen, I was successful after three times. (once noticing a tiny hair or something foreign showing thru the viewfinder but not on the test picture)

A test against the cloudy skies. Now no dust on the sensor. :)