I consider Ars Technica to be among the best technology related blog (and matter of fact, according to Technorati, it is). These guys do an excellent job covering a lot of news and topics mixing their own brand of hilarious humor in it. I first stumbled on this web site while searching for a review of iPod Nano. These guys had the best review available and not only that, they took the reviewing business so seriously that they actually ran the Nano over with a VW car to stress test it! That was some review. Ever since then, it’s been exactly three years now that Ars is my most regular source for all things technology.
Here is an excellent article explaining the basics of 64 bit computing by Ars: An Introduction to 64-bit Computing and x86-64.