Below are some of the series of WF articles that I often read:
1. Stick to the Learning Series of sashboard blogs. This is what I see most, and I feel quite comfortable with my learning ideas.
Http://www.cnblogs.com/carysun/archive/2008/10/21/1209612.html
2. Xiao Shatian's WF learning notes series have very detailed knowledge points. Almost all the WF knowledge points you want to learn can be found in this series.
Http://www.cnblogs.com/xiaoshatian/archive/2008/03/18/818615.html
3. wxwinter (Winter) blog's WF series, from which you can learn some workflow instances and some development skills.
Http://www.cnblogs.com/foundation/articles/527854.html
4. guoyong. from getting started to mastering the series, Che's WF seems to be translated or directly a chapter in a book. Unfortunately, it is in guoyong. the Directory Index cannot be found in Che's blog. The following is the Directory Index I searched online. It is also an article I published earlier. This series of content is very detailed, it is really a beginner.
Http://www.cnblogs.com/sharezone/archive/2009/04/30/WF.html
I will add some other WF series one after another.