Most dSLRs will get sensor dust eventually - how dusty and how soon will depend on your environment, and the lenses you use. Only a few come dSLRs come with an ultrasonic sensor cleaner built in - just Olympus currently.
Sensor dust is currently a fact of life. The good news is that it's also fixable, by you, at low cost :)
Remember you're not actually cleaning the sensor itself, you're cleaning a low pass/IR filter in front of it. Obviously I've been careful, you'll probably invalidate your warranty, and I may have been lucky - there is a serious risk of sensor/shutter damage if you're clumsy, incautious or just plain unlucky. If you have any doubts, take it to be professionally cleaned at an authorised service centre!
This has worked for me, there's no guarantee it'll work for you. Proceed at your own risk...