are there any services that will take apart the lens and clean it? I have no freaking idea how it got in there. There is probably some magnification effect, but it appears quite large. I've tried blowing the lens with compressed air to dislodge it with no luck.

otherwise, they should be able to provide you with an authorized service provider in your area (I think it's only like $40 for canon to clean it if it's out of warranty, though). there's a way to search for one on their site.

i don't think it would affect the image much, but if it bothers you enough, then get it done.

to the human eye.
You'll have more loss of detail from the chip or film grain, than a few specs of dust will cause.

don't worry about it.