Today, in the agile community, there are dozens of newsgroups spanning many topics. Here are a few interesting ones I regularly track and follow:

Extreme Programming:
http://tech.groups.yahoo.com/group/extremeprogramming

Domain Driven Design
http://tech.groups.yahoo.com/group/domaindrivendesign

Lean agile
http://tech.groups.yahoo.com/group/leanagile

Lean development
http://tech.groups.yahoo.com/group/leandevelopment

Agile testing
http://tech.groups.yahoo.com/group/agile-testing

Agile usability
http://tech.groups.yahoo.com/group/agile-usability/

Do a favorite newsgroup? Do share.