Here are a few other sites that have the same basic preoccupation. Enjoy.

Living Dead Covers – From Portugal
The Graphic Design of John+Mary Condon
Penguin Science Fiction
Things Magazine
Eric Carl’s Photostream
Insect 54’s Photostream
Judge a Book
Joe Kral
Grain Edit
The Designer’s Review of Books
Critical Terrain
Kyle Katz
The Book Cover Archive
Old Timey Paperbacks
The Casual Optimist
Dan Meth’s Photostream