Playing with the iPhone, I found a cheap easy macro lens. I have a jewelers 10x lens that has an LED light with it. I just attached it to the iPhone with a couple of rubber bands and got some pretty decent pics. Cool thing is it's still a great little hand lens for looking at stuff. There is a little cropping necessary but nothing serious. Cost was about $20 from amazon...
Penny, cropped.
Here is the full iPhone frame to get an idea of the amount of cropping needed. Less if you get the image centered a little better than I did.