Before sending funds, ask for a scan of both sides of the title to see if it hasnt got a lien (this is for 90% of the states)...dont assume nothing when it comes to a title. People are walking away from there houses at the moment, a car is nothing in the sceme of things at present.
If the title is clear, he needs to sign it and if there is a spot (depending on the state) have him write your name and details on that spot with the selling price. (You dont actually get the title put into your name) It is then surrendered to US customs in order to ship your car. You may get it back in OZ..thats a 50/50.
Get a bill of sale with date, name of both parties and addres's, the Vin number, year make and model and the selling date also stating that it is clear and free of any lien's and if your doing this via Evilbay (good luck), get a Notary (JP) to sign/witness it
Hope that helps
Matt