I got this from Avery Australia - for DL33 labels in MS Word, define a new label type as follows:

Top margin 1.6 cm, Label height 2.55 cm, Side margin 0.3 cm, label width 6.8 cm, vertical pitch 2.55 cm, number acroos 3, horizontal pitch 6.8 cm, number down 11.

Steve

(Sorry, I am an Aussie and we work in metric)