Most maps provided on this web site are free for personal or commercial consumption. In other words, feel free to steal my maps. If any other license applies to a map, I will specifically state so in that map’s blog post.
I primarily use Campaign Cartographer 3 and its various add-ons for my maps. I also use a fair bit of Photoshop and occasionally experiment with Google Sketchup or various other methods.
By the way, I’m a hobbyist, not a professional, so please excuse the poor quality while I climb the learning curve. But hey, what did you expect for free?