Google is your friend- try using it some time. It's on PC and Mac a simple search could've told you that.
I remeber Postal...kinda fun. Lot's of funny things at your disposal. I prefer the "cat siliencer" Postal 2 is out also available for PC and Mac. Not much innovation between the two, but fun still.
I very seriously doubt you will find it at a typical store or game store for that matter. Look on Ebay or the game's website.
OMFG Postal is the most sick perverted game i have ever played! I consider myself i pretty harsh gamer. But not one sane person among us can say we didnt feel bad about smacking some dogs head on with a shovel! Ban this Game everywhere.
Dude, i never felt bad running over mothers with strollers, or old ladies and dogs in the Carmageddon games, neither did it bother me wacking everyone in Postal 1 and 2. For f*cks sake, it's a VIDEO GAME. If you don't like it, don't buy it or play it, but don't go around saying it should be banned just because it's not your kind of game. Cause that is just plain bullsh*t.