Before you get some "not so nice" comments, I'll say this--Seek(search) and you shall find. But there is a sticky that has all the stock rom links:
http://forum.ppcgeeks.com/showthread.php?t=42741 You would flash the stock rom the same way you flashed the custom rom. The only extra step would be relocking which would be important if you were sending the phone back to sprint or taking it to a store for service/repair.
p.s. next time try the search function as it cuts down on the clutter of new posts being put up that have already been answered and are easily found using search