This is a (personal) list of articles dealing with unit testing that I like. I have chosen to include material that is longer than the usual (short) blog posting. I encourage readers to give more objectivity to this subjective set by submitting in the comments what they preferred ;o)
Test Flexibly with AspectJ and Mock Objects
Automation for the People: Continuous testing
Exploring The Continuum Of Test Doubles
End to End, or, Another Run on the Hamster Wheel of Life
In Pursuit of Code Quality: Unit Testing Ajax Applications
Apply Test-Driven Development to your Database Projects
What It Means to Mock: Isolating Units for Testing
Unit testing and Test Driven Development (TDD) for Flex and ActionScript 3.0
Unit testing Web 2.0 applications using the Dojo Objective Harness
A Guide to Testing Rails Applications
Additional unit testing article resources
TestDriven.com – Articles Directory
IBM DeveloperWorks
Quality Assurance Links Directory – Articles Section