I have "Road Race Tactics for Amateur Cycling Teams' by Harrison, from Roadbikerider.com, and "Strategy & Tactics for Cyclists" by Arnie Baker, also from Roadbikerider.com. Both are good, I endorse them, and they are a bit different so it's not a waste to get both.

Also there's the Australian blog "http://www.cyclingtipsblog.com/" that has some good stuff hidden here and there.