Planetizen is an on line about city planning 

and urban development with great articles.  

A few are listed below:

Street Design

http://www.planetizen.com/node/39815

Suburban Makeover

http://www.usatoday.com/news/nation/2009-07-15-urbanburbs_N.htm

Roundabouts

http://www.planetizen.com/node/39774