My sis and her husband live in Australia and last year we were lucky as our Mum & Step-Dad were going over to visit before crimbo so took our presents with them. This year however we're not so lucky. I have collected a few things together so far for them both, all small and lightweight such as silk scarf I painted myself, some jewellery I made myself, I just generally keep my eye out for small or at the very least lightweight items I can send as presents for them. I will probably be posting it soon and send it via landmail so will take a few weeks to get to them but is cheaper.
If your stuck on things to send that aren't too heavy or bulky, there's always things such as notelets, t-towels of place your living, soft toys, small games etc..
Hope I've been of some help :o)