Can leather seats be recondition?

I was just wondering - you know how, eventually the shiny surface wears away on your leather seats and it looks all dull and grey...? Are there places that you can take your seats to that can restore their original shine and luster? Can you do it yourself? How/where? Please help.

Thanks,
Michael

Thanks for the info-

Well thats good to know! There is a guy that wants to do an even swap - my mint 96 GT black cloth seats for his black leather 95 GT seats. His seats have no tears or rips, but I can see where the driver's seat is starting to lose its shiny finish and expose the dull grey. I'll look into this, locally, and see if anyone around here can refresh the leather and what the cost is. I'm replacing the seats in a few weeks anyways with suede Corbeaus, but I figure I can sell the leathers for more than the cloth so I'll probably go ahead and trade seats with the guy.