These techniques seem to be getting a lot of attention lately, but they've been written about extensively for a long time now. You don't hear much of these older books, but they're well worth looking at if you're interested in this topic:

http://www.amazon.com/The-Memory-Book-Classic-Improving/dp/0...

http://www.amazon.com/Use-Your-Perfect-Memory-Techniques/dp/...

http://www.amazon.com/The-Memory-Book-Remember-Anything/dp/1...

There are many others as well.