I did a bit of searching, and this is what I came up with. You can listen to Garrett's music streamed from his website. As far as places to buy/download, this and this seem to be places to go to. The first is free, and seems 100% legal as far as I can tell. The second uses Amazon MP3. Only 6 of his 25 or so songs are for sale, though, at least as far as I've been able to tell.

If anyone has more information than me, please do comment.

Edit: A search directly on amazon led me to A Dream Between and a whole bunch more tracks that aren't on that apparently.