If going with someone who already ice fishes:
License
Offer to pay for bait or ask them what they are using and go buy at the bait shop
Warm Clothing (layers is the key, make sure you have warm boots also)

Others to consider if going with someone who already ice fishes:
At least one rod designed for ice fishing, prefer with an open face reel
Small assortment of jigs and hooks from local tackle store
Hand Auger
Ice Scoop
Minnow Bucket with minnow net and minnows for whatever species you are targeting
Ice spikes (just in case the worst happens and you fall in)
Tip up if you plan on doing this type of fishing
Chair or bucket to sit on
Ice bobber if you prefer that type of fishing (the bobbers made specifically for ice fishing really shine compared to warm weather bobbers, so make sure you buy those specifically)

What you need if you are fishing on your own:
License
Some sort of auger (you need a hole in the ice)
Ice scoop to get ice out of augered hole
Fishing Rod(s) prefer with open faced reel
Tip up(s)
Ice fishing tackle (jigs and hooks for setting up tip ups and rods)
Bait / Minnow Bucket
Chair or bucket to sit on
Ice spikes
Warm clothing, especially boots. Dress in layers if possible
Ice bobber if you prefer that type of fishing

That should be enough to get you on the ice and see if this sport suits you at all.  In a further post I will discuss bringing your ice fishing game to the next level and will discuss the reasons for spending money in electronics and so forth.