I'm happy that you like my work; I'll be posting more maps, and a tutorial of my process here within a couple of weeks/months. The short answer is that I pretty much create all of my own textures, patterns and brushes in Photoshop using images I've captured myself with a camera. But you should see what I mean a little better when I post my tutorial.
I do, but I'll have to see whether it's small enough to upload at full resolution. They do have some size requirements here, and usually I'm trying to figure out ways to squeak under it with my smaller maps. I'll compress, and see what I can do.
I have suggested it to a great group called Cartography-Guild on deviant art. you should check it out if you want to see other inspiring work or be connected to a community of great talent and people. They are connected to a great site called www.cartographersguild.com