Here a few art blogs that are fairly interesting. The bloggers were all interviewed for a recent issue of Art in America.
Art blog mostly about Philly but still of general interest
Tyler Green's blog about modern and contemporary art
A Portland, OR based blog
And a Seattle-based blog
Finally an artists website called DeviantART mentioned on CNet
I'm not totally sure what DeviantART actually does for an artist but it is worth a look at least.