Nikon makes the ML-3 IR release. It's rather pricey.
Any 10 pin socket compatible release will work. If it's listed for other 10 pin socket cameras, it will work on the D800.
There are a lot for sale on eBay. B&H and other online stores list a few choices too. I got a Promaster brand RF release at my local camera store; I'm happy with it.
Gary in SE Michigan, USA. Co-organizer of the Southern Michigan Chapter Nikonians membership - My most important photographic investment, after the camera. D4, D800e, D300, D90, F6, FM3a (black), FM2n (chrome) YashicaMat 124, Graflex Speed Graphic 4x5 My Nikonians Gallery & Our Chapter Gallery