It's called a keyhole or periareolar. I had it done and posted pics -- they're in my gallery but it looks even better now a year and a half after surgery. Now I'm going to engage in some very transparent Beverly Fischer evangelism...tee, hee...she's great! I swim all the time, take my shirt off, run around topless, etc. with no problems, no scarring. I also have fairly good sensation.
You've got to be realistic about your surgical options, though. Your boobs need to be pretty small to expect a good outcome from this surgery. It isn't going to come out looking good if you're any larger than a B. All that extra tissue is going to pucker up and look messy. If you're big, you'll pretty much have to go with the double incision w/nipple grafts.
If you'd like to see updated pics of my keyhole, I'd be happy to take some new ones.