Other than Hondarake, which is pretty much useless to me, and o-su, which doesn't have many people selling books, I can't find any avenues. It really doesn't help that Australia doesn't have a nationwide bank like the JP bank, which makes sending money really really easy...
I've already donated one series (W-Juliet) to my own secondary school, and will probably donate at least one/two more (Card Captor Sakura, Ouran Koukou). But what do I do about the more violent ones that they probably wouldn't want?
Flame of Recca (all 33 vols)
Rurouni Kenshin (28)