And it's pretty darn good, too. Kinda reminds me of a cross between Neverwhere and American Gods. Both Neil Gaiman, I know, but it's definitely not a bad thing to get compared to him! The whole thing's available online, but if you email the author, he'll send it in PDF too. There's a sequel also, and if you ask, he'll send it to you as well. If you don't feel like reading it directly in HTML, I've asked him for the PDFs of both, and would be happy to share.
Darkside Update:I've received the PDFs from the author, and they're pretty high quality. Definitely to be recommended over reading it directly on the website. Let me know if you want them!