If you have a lot of money or a killer insurance plan I have heard of a lazer treatment for freckles. Basically the lazer uses a frequency that penetrates the skin without harming it but vaporizes the mellanin. It will fade prominent freckles and remove faint freckles but from what I understand it's very expensive.
The technology is similar to what they use to remove large birth marks. It's supposedly painless and requires no recovery time. Just make an appointment and walk out a little less freckled.
Disclaimer: I typed all the above from memory. I saw this on a TV program on PBS several years ago. I've no idea if this is still used or anything else about it but what I said above.