Slightly off topic perhaps but as the recipient of the occasional ebay click and send satchel I have noticed the plastic pockets not always sealed - had one the other day where the paper 'label' could have almost slid out. The senders really need to cut or fold the label small enough so they can completely seal the plastic pocket or perhaps put some tape over it.

eparcel is available for high volume sellers, more info here:

http://auspost.com.au/business-solutions/eparcel.html

As for options (general) for printing address labels, I love my speedy little Dymo LabelWriter, saves me firing up

the normal big printer.