country specific domain name SEO question

I am about to begin work on a project. Although I am based in Australia it will be a project with international scope and an international membership. It will however feature a lot of Australian content as well as membership. I already have the .com domain for the project but should I get a .com.au domain as well and host the project from that domain (with the .com forwarded) - or vice versa?

Hope that wasn't too confusing.

Oh, and the question relates to SEO. Which would be better for SEO. (which I am obviously very new at!)

I'd register the .com.au (primarily to keep any potential competitors from registering it), host the site on an Australian server, and then redirect the .com.au to the .com TLD. If you're really worried about latency issues with your international visitors, you may want to consider hosting the site elsewhere, but make sure that your Australian visitors don't get left out in the proverbial cold if you do so.

Also don't forget to create a Google Webmasters' account at http://www.google.com/webmasters/ either. :)