Take a look at the getting started information and familiarize yourself with the concepts involved in multiboxing. Taking the time upfront will greatly increase your leveling speed and effectiveness. The forums have valuable posts stickied, read up!

Two of any class are viable to multibox, just do your research and make use of the search function here, the odds are good all the newbie questions you'll have have already been discussed in detail.

If you have not already had your expectations set regarding setting up your first multibox configuration: it will take a little time and effort getting used to it and setting up whatever macros etc you might need, but the reward is well worth it.

-Jay