Couple ways you could do it.

First, the right way: You need the events (LabelName)OnWheelUp, and (LabelName)OnWheelDown. Then, the bang, !LabelScroll. See the "Bang Commands" section of the xLabel help file for details on how !LabelScroll works. You'll also want to check out "Scrolling Setup" which you'll find in the "Text Configuration" section.

Another way you could do it is hook the text label inside a container label, and move the text label up/down with the mousewheel. With this method, you could also restrict the label's movement area and drag the text up/down, which would be kinda cool.

For either way, you'll probably also want to define (LabelName)FocusOnEnter, so the mouse events fire without having to click the label.

If that doesn't help, be a little more specific on exactly which part you're stuck on.