It was printed on a LightJet using the normal driver a LightJet comes with (very expensive printer).
Could easily be printed on a large format printer using photoshop or a nice RIP to print with. Large format printers run about $5000+ and a RIP (just a complicated driver for the printer) runs 3000 - 5000 usually print shops have these tools, or somtimes succesful artists can afford them. (thats why I use the print shop...lol)
Pretty spendy stuff, but if you have photoshop CS3 or better, this is pretty easy to do and send off to a pro shop.