You need a four channel GROUND controller. Most 4-channel controllers are for aircraft, which you cannot use for ground equipment. I don't know why not, some FCC reg most likely. Futuba is the name brand most recognized.
One type is 72 mHz, the other is 75 mHz, but I do not recall off hand which is ground and air. My local shop has the one I need (I have the same Tiger kit) and it runs just under $200. I've been putting off ordering it until my kit is built. I have seen these things at local Hobbytown USA (do a search to get their website) and online at www.towerhobbies.com. I bought my first Tamiya 1/16 Sherman from these guys and they have just about everything you need in the RC hobby world. Look up the Tamiya kit and it will tell you the accessories necessary for the kit.
The controller comes with the receiver and servos necessary to operate the various functions of the tank. The other items you will need will be AA batteries for your controller. Your other big expense will be the 7.2v battery and charger. This is to power the tank. Your RC hobby shop, no matter how lame, will carry the charger and battery. Radio Shack may also stock the proper batteries and chargers since they have an extensive RC selection around holidays. Normally get a couple of batteries since they last about 10-15 minutes when fresh.
Top end rechargers will charge your batteries in about 15 minutes and also include the ability to recharge the battery from the car battery or cigarette lighter. The cheaper type that are found in the RC department of local Toys R Us or Wal-Mart normally take about 4 hours or even overnight to charge the battery.