Battle Moveset

A Good Moveset for Snorunt would have to be this:

Attacks:

Ice Beam
Shadow Ball
Double-Edge
Hidden Power Ground OR Crunch

Items Attached:

Choice Band

Preferred Nature:

Timid

Strategy Using Snorunt

Snorunt base 50 stats all round doesn't leave it too much of a threat against the majority of pokemon used these days. It type leaves it with only one resistance, and it has a limited movepool.
To make up for that lack of power, Choice band is the way to go. Since Snorunt won't last long anyways, Double edge is worth the 1/8 HP loss.
Ice beam is necessary for STAB, since poor Snorunt has nothing much going for it.
For the last slot, I suggest HP Ground or Crunch, since it can't do much else. HP Ground is mainly for possible Fire types that will be used against it, and it will most likely get KO'ed by a flamethrower from a fire type.

EV Corner:

Max out the EVs in Attack and Speed for Snorunt with any remaining in HP

Strategy Against Snorunt

Base 50 Stats all round, not much of a move pool, plenty of weaknesses, one resistance. *Thinks very hard* I know! We’ll attack it and it’ll die. Simple, hit it (with anything that has a respectable attack stat and that isn’t Ice typed) and it will faint, I can’t be any clearer.

Contest Moveset

A good Contest Moveset for Snorunt would have to be this for the Cool Contest best with Lonely, Adament, Naughty or Brave Nature:

Attacks:

Hail
Ice Beam
Blizzard
Shadow Ball

Items Attached:

Red Scarf

Strategy Using Snorunt

If you do the attacks in this following order you should have very few problems; 1st - Hail, 2nd - Ice beam, 3rd - Hail, 4th - Ice beam, 5th - Shadow ball

Locations in Games

Ruby/Sapphire/Emerald Shoal Cave Colosseum Trade from R/S/E Fire Red/Leaf Green Trade from R/S/E

Animé Appearences

Snorunt has had a couple of Animé Appearences. In it, it stole Ash's Badge Case and Ash had to chase it to get it back, in doing so he gained Snorunt's trust and Snorunt eventually joined Ash. All Subsequent Appearences are under the control of Ash Episode 385: Catch Snorunt! Episode 386: Rescue Ralts! Hurry Max!