Wing loading is just the weight of the plane (in ounces) divided by the area of the main wing (in square feet). For example, a DPS wing is about 48" x 12", so 4 square feet. If your DPS weighs 5.5 pounds (88 ounces), you divide that by 4 feet, and you get a wing loading of 22 ounces/ sq.foot.

There's nothing inherently good or bad about wing loading. The lower it is, the slower the plane can fly (and the longer it will glide without power), so trainers typically have lower wing loadings than war birds, for example. A typical balsa trainer has a wing loading in the neighborhood of 16 to 20 oz/square foot, down to something like a SIG Kadet senior that might be 14. Planes designed for 3D acrobatics (crazy stuff that you didn't think airplanes could do, like hover), also have low wing loadings, typically 16 or less.

All things being equal, you probably want to keep your weight down as much as possible, but if your planes fly fine, don't sweat the numbers.