Hello Andrew,
I bought one not long ago, you'll need two bits a Canon EOS T-Ring ($35AU) and the adaptor ($39 for a 2", $36 for 1.25"). I didn't do a lot of shopping around and got mine from Bintel (
https://www.bintelshop.com.au/welcome.htm) as part of some other bits and pieces + postage. My scope takes both so I went with the 2" adpator for more light capture. I haven't had a chance to use them yet, but they fit the camera and the scope very nicely. The adaptors also list one for SCT scopes (same price) as apposed to Newts'/Refractors I guess. As I don't have an SCT (yet) there will be others who may advise for some other bits to enhance your imaging for an SCT, if that's what you have, otherwise the basic setup is these two bits. Good luck, I hope to actually start imaging one day, slowly but surely .... BTW these bits will be used with my new Canon 400D I have had for a few months (early x-mas present), by all reports it should be a reasonable set-up with the 400 doing well depending on skills and experience, of which I have very little.
Cheers,
Paul