Nice gun, be prepared for the heavy recoil. Mine is a 6" and it is quite a handful, even more than my 357 Ruger SP101 3".
The ammo can be found on the net at CheaperThanDirt.com for about 0.60 cents per round.
Get good earplugs too, the 41 is like a stick of dynamite going off in your hand.
But it's fun to shoot.