As Gus said, if ALL other factors are the same, then a lower wing loading will result in a slower flying plane. But there are numerous variables that affect flight (and landing) speed.

If you're considering differant, but quite similar aircraft, you can often assume that lower wing loading will have an affect on flight characteristics though. Say two trainers of similar wingspan; my assumption would run something like this; planes 'A' & 'B' have almost identical wingspans, they use the same engine size and are similar in length and tail surfaces. They are both high wing types and both have a flat bottom airfoil and similar dihedral. Therefore, the one that weighs less will fly slower.
Dennis-