By saying "spectrum", I think rlipsett was referring to the 2.4 ghz systems that have just come out. Without going through the technology (which I don't understand), these transmit without using a specific frequency, so you never have to worry about what channel you are on or having someone shoot you down. The first manufacturer was Spektrum, which was somehow affiliated with JR. Futaba came out with its own system, called FASST.

I wouldn't say you need to spend the extra money at this point if you don't want to. I would recommend that you get a computer radio, however. You may not think you need 6 channels because you don't plan on flaps or retracts. There are several advantages to a 6 channel computer radio that you will use: end point adjustment (using the transmitter to precisely adjust how far your servos move), exponential (makes control surfaces less sensive near the center while retaining wide range of motion) and dual rates are a few. Most important in my mind, however, is the ability to use dual aileron servos without a "Y" cable. Many sport planes today use dual aileron servos, so this is a vital feature.

A good entry level computer radio is the Futaba 6 EXA. It is about $160-170, so it is not much more than an entry level 4 channel.

I also agree that you might want to start with more of a "second plane" like a Goldberg Tiger or Sig 4-Star