Doug Ellison has a great article in the "Planetary Report"
"Bootleg Postcards: Amateurs Participating in Space Missions" is the title, in the January/February issue, published by the Planetary Society. I just got my issue yesterday. It's about the great image work (among other things) done by amateurs.
Unfortunately, it doesn't seem to be online in this form (with lots of pictures), but there is a podcast here.
And of course, you can see this work all the time on Unmannedspaceflight.com