Four new tier vendors have been placed in both the Alliance and Horde shrines in patch 5.4. Each vendor handles a particular difficulty of gear -- LFR, flexible, normal, and heroic. These vendors are all in the same area as the challenge mode gear vendor, making them ridiculously easy to get to. If you have tier tokens from any difficulty, simply visit the appropriate difficulty level vendor and turn them in.
I have to say, after an entire expansion of flying back and forth to the far reaches of Pandaria just for some tier gear, it's nice to see these guys are in someplace well and truly immediately accessible. After a day's worth of raiding, the last thing I want to do is travel around hunting for the rewards I'd already obtained. That said, it would be nice if they'd add a vendor that carries all the old tier from this expansion as well -- might as well move everyone in close, now that we're nearing the end of the expansion. Good luck to those intrepid souls stepping into LFR today, and remember -- this time around, your gear is closer than you think.