Jeff Clark has spent a lot of time getting NBA bloggers to collaborate and put together the best collection of previews ever created. Throughout the month of October, all 30 teams will be previewed, typically by several different blogs.
Here are the links to the Atlantic Division previews:

Celtics 
Celtics Blog
LOY’s Place
Celtics 17
Red’s Army
Celtics 24/7

Nets
Hooplah Nation

Knicks
Straight Bangin’
Posting and Toasting

Sixers
Passion and Pride

Raptors
HoopsAddict

Archives
CelticsBlog NBA Page