RubyBlogs and such
Other blogs & wikis:
Jerry Weinberg's SHAPE Forum and writing and consulting blogs
Esther Derby's insights you can use
Johanna Rothman's management blog and hiring blog
Don Gray's TikiWiki, old blog, An Alternate Reality blog and Systems Thinking blog
Alan C. Francis' blog
James Shore's blog
Christian Sepulveda's Pivotal Labs blog and older Agile Ramblings
Martin Fowler's bliki
Dale Emery's blog
Ward Cunningham's C2 wiki a.k.a. the Portland Pattern Repository. This is where the wiki concept was born. Unfortunately, it seems to have become inhabited by people who have a lot of time on their hands (and therefore can overwhelm other users), but are more interested in wikis and philosophy than in writing articles about software development. Flamewars and misinformation abound, and make the useful content hard to find.
The Object Mentor blogs: Uncle Bob, James Grenning, Bob Koss, Michael Feathers, Micah Martin, David Chelimsky
Laurent Bossavit's blog
Bruce Eckel's blog
Jeff McKenna's Agile Action blog
William Caputo's blog
Rachel Davies' blog
Lidor Wyssocky's blog
Adrian Sutton's Symphonious blog
My, this list is getting long....
Artima Developer community, and weblogs
Agile Project Management http://www.deadfishsociety.org/