Heya WA Surf!
The one you want is here:
www.locosystech.com/en/product/Previous-Generations/locosys-previous-generations.htmlCouple of WA retailers stock these, ring around and you'll find one.
Then you need a 2 gig Sandisk SD card, and a card reader. (about $15 each from any electronics retailer like JB hifi)
And you also need a waterproof armband. There's a guy on here called johno who lives in the phillipines I think, who makes these (jp11?)... I have one of the first ones he made and it's still going strong. Also I saw one on here:
windsurfing-koprivnica.net/news.php?item.2361.11Failing that a good old aquapak might be easier to obtain, although it won't fit the GT31 as snugly.
Plenty of speed crew on here who are more than happy to help, and when you join a team you'll notice that your circle of windsurfing buddies will triple! It's great to be able to blog about your sessions, good to push your boundaries, all up it's a great addition to your gear bag.