Tim O'Brien, one of the most skilled artists working in illustration today, did a beautiful painting of Barack Obama for the cover of the March 20th issue of Rolling Stone.
If you have not seen this, go to your book store or magazine stand and check it out. Though there are other items of interest in the issue, the cover itself is well worth the price of the magazine.
On Tim's blog, you can see an earlier version of the cover and read about the changes he made and a little on how he went about making them.
Tim O'Brien's blog