The spots in the sky are sensor dust. Check out this link as to how to clean it.
http://www.pbase.com/copperhill/image/39082096
This is the best way I've found to thouroughly clean your sensor. Its not hard, just be careful not to let your shutter close while cleaning.
As far as the dust in the viewfinder, they are different and won't affect your image but if you want to clean it out you'll have to find out how to take your viewfinder apart (like you were going to replace it). I've never done it so I can't help you there. I just live with the specs on the viewfinder as they don't affect anything.
I hope that helps.