I did it last year in Texas, on a charter from the outfit that normally operates out of Florida. It was pretty darned cool. After 15 cycles, I was starting to feel not so well. They give you information in advance about special medication that you can have your doctor prescribe that will prevent this from happening - I'd highly recommend you do this, even though it involves a trip to the doctor and special ordering one of the medications (since it's not stocked in normal pharmacies).

I highly recommend the experience, and would do it again in a heartbeat should the opportunity arise. It takes place on a 727 cargo aircraft that had only minor modifications made to support 0G flight. The flight is a Part 121 operation (the same as regular scheduled passenger flights) with only minor waivers granted, so the FAA at least considers it as safe as a regular passenger flight.