Here's the Ryan Sook Gallery webpage. Sook is the current artist of DC's Arkham Asylum: Living Hell book, and has done turns illustrating BPRD and the Spectre, among other things. He's good, and is capable of doing a dead-on Mike Mignola art impersonation.
Also, here's the site of another excellent illustrator, Tommy Lee Edwards. he's gone on to do many interesting projects for several companies, but he's never topped his work on the Vertigo/Helix series Gemini Blood in my book. I'm contemplating writing a piece on Blood, which was an outstanding and overlooked book in my opinion.