Steve Dembo, a highly-read ed tech blogger, has written a series of excellent posts on "30 Days to Being a Better Blogger". Day #1's post is here.
You can find great blogs in various content areas listed on this wiki, built as part of a project of a school leadership network.
A great example of how teachers can engage in rich professional development through technology can be found at this blog post. Be sure to read the comments, too.
Technology
A middle school teacher in a remote town in Canada connects his students with resources around the world.
A teacher in a Title 1 school with many ELL kids who uses technology constantly
A remarkable collection of free tech tools, often with tutorials.
One of the best writers about how technology is changing learning and teaching.
Removing the "e" from E-learning
Good writing about integrating technology into the school day.
Title 1 Teachers
Learning is Messy (remarkable media- rich projects are done in this classroom with very outdated computers)
Teaching ELL Students
Larry Ferlazzo provides (almost) daily links to resources on the web for teaching ELL students.
Nik's Quick Shout gives good reviews of tools to support teaching ELL students (and others)
Special Needs Students
All Together We Can A good blog on adaptive technoogies for special needs learners.
Content Areas
The Book Whisperer (a 6th grade language arts teacher)
Small Voices is the podcast/blog of a kindergarten class in Georgia.
Dy/Dan is an excellent blog about teaching math and about teaching in general.
General Interest
Blogboard (Teacher Magazine provides links to teacher blogs of interest several times a week)
The Tempered Radical (a 6th grade teacher in North Carolina talks about the conditions of teaching today).
Teach Learn Connect The blog of a first year teacher who was in the UWB program only a year ago.
Also, check out the selected posts from blogs that Jane reads on the Jane's Shared Posts from Google Reader
page. These update automatically when she marks something that she reads as "shared" so check back every now and then.
At these sites, you'll find groups of educators who have created virtual social networks (usually on platforms similar to MySpace of Facebook, only more private) to collaborate and to support professional growth. You can join many of these.
Classroom 2.0 Is a rich and ever growing network of teachers exploring the uses of web 2.0 tools for teaching.
Setting the Standard is an incredibly rich social network of teacher leaders. Here, they post there literacy lessons. They upload videos of themselves teaching math concepts. They ask one another questions and discuss different approaches.
Online Projects 4 Teachers is an network of teachers who want to build collaborative prorjects with other classrooms.
Social Networks in Education lists multiple social networks for teachers by grade level, subject area, geography.