I don't see the need yet to perform any (manual) sensor cleaning. After two years of using the Olympus E-500 and changing lenses, there hasn't been one single speck of dust in sight. So it must be true what they're saying about Olympus' dust reduction system (the most efficient on the market today)...

We do not see things as they are. ǝɹɐ ǝʍ sɐ sƃuıɥʇ ǝǝs ǝʍ