Easier said than done. But I've done it.

I have everything that came with the phone, box is like new. (If anyone in Australia wants some extras, contact me)

Contacted the lost property department of RailCorp, and provided them the IMEI of my lost N900.

Biggest problem: That day there was track work going on, so it was some random bus company running the buses for that section.
Contacted all possible bus companies... nothing.

Railcorp told me that bus companies are supposed to send them all lost property, but most don't.

I assume that some random person got it. But I bet that whoever it is they can't even turn it on.

If there is a way to easily block or locate the phone using the IMEI, I'd like to know.