That Ricky guy has no clue what he's talking about, this is why you shouldn't trust any "reptile store".
There's only 4 people in the US that milk snakes, hobbists who own them obviously don't do that. Getting a venomous license doesn't teach you how to do that, doesn't give you permission to do that, and that doesn't make it so that they can't envenomate you. A snake can be milked then turn right around and bite & envenomate you. they don't suddenly become 100% empty after "milking". Milking is really just having them strike a cup and they don't release all their venom in one bite. They can control the amount of venom they deliver which is why you have dry "warning" strikes.
A venomous license just gives you permission to own a certain amount of them, to obtain a permit it's about $100 a year and you need 1000 hours of verified experience to get one.
Often times you don't even need one to own venomous. Some states have it so that "exotic venomous" are okay but venomous snakes naitive to that state are not. Some are okay with them both, no permit needed, but one or two are the exception. (EX. Texas is okay with all, no permit required, except for "protected naitive venomous" such as the timber rattlesnake in which case you'd need a permit.) and some just ban them outright. You'd need to check your state laws.
Yes a surgery does exist. Snakes that get it done are called "venomoid". Most reptile classifieds have a special section just for venomoids. http://market.kingsnake.com/index.php?cat=105 Here's one that actually has more selection. http://www.faunaclassifieds.com/forums/search.php?searchid=1494345
There's many different ways to do it, but the best and most efficent way is to simply remove the venom glands. It's not that invasive, barely leaves a small scar, and best of all if it's done properly there is no risk of envenomation.
Another way is to cut the duct between the gland and fang, but this method has been known to fail when the duct regenerates. If you ever hear about a supposedly "safe" venomoid who has envenomated it's probably because they had the ducts severed and it healed.
An envenomated snake is obviously in captivity so it wouldn't need it's venom to kill since it's probably fed pre-killed or f/t rodents. They can still survive just fine without venom. They do still have loads of sharp teeth, removing them is pointless because they grow back.
This procedure is highly controversial, some say that it's "animal cruelty" and others say that it's done for safety methods and show that the surgery can be done properly by a vet and that sucussful venomoids don't show any signs of stress/sickness. Most people agree that it is wrong when amateurs do it since they often don't use anesthesia and they just cool it down so that it can't really move, now THAT is cruel.
Here's an official site on it http://venomoidinc.com/home/index.php?option=com_content&task=view&id=13&Itemid=29
Here's a FAQ on it from kingsnake.com http://www.kingsnake.com/aho/faq/venomoidfaq.html
Here's an article that even shows you pictures of how it's done http://www.venomousreptiles.org/articles/55
Here's another kingsnake.com FAQ, biased but still a FAQ http://www.kingsnake.com/snakegetters/demo/vet/venomoid-faq.html
EDIT: @Madsnake: If you live there you probably know more about it then I do, I live in southern California and I assure you that you will not find a permit at walmart here. I don't even think our walmart /has/ a hunting section period. The $100 a year one is for Florida and I'm sure that is correct. http://www.preservevenomous.com/venomous_reptile_laws.htm
I just checked Google for another example on venomous snake laws and stumbled upon the Texas wildlife department site. This is copy&pasted from there.
Native Venomous: No permit required
Exotic Venomous: No permit required
Protected Native Venomous: Permit required
Timber Rattlesnake (Crotalus horridus)
Texas Parks and Wildlife Department
4200 Smith School Road
Austin, TX 78744
Perhaps it's outdated or something, either or it was just an example. Like I told the asker, he'll have to check his own state's laws.