The subtitle to Logged On and Tuned Out, by Vicki Courtney, states "a nontechie's guide to parenting a tech-savvy generation." That is pretty much the gist of what her book is about. It's written for parents who are not quite up to speed with the technological state of affairs that our children find all too comfortable.
An acquaintance of mine, who is about my age, has a difficult time managing the mundane task of e-mailing. She is, no doubt, unaware that she is at least two steps behind her 6th grade daughter in that her daughter considers e-mail to be a thing of the past. Enter the world of constant cellphone communication, IM'ing, texting, digital photo and video uploads, and the social networks such as MySpace and Facebook.
Courtney presents a concise primer on the way such technology works, as well as outlining the potential hazards awaiting a young, immature generation. Be forewarned, however, that her writing style is geared for the extroverted female reader, who probably spends time with "the girls" at the mall (e.g., I am so-not into that).
Recommendation: If you have tweens or teens, and are not tech-savvy, I'd recommend you read Courtney's book. If you already have a good handle of the communication technology out there waiting for your children, then a cursory inspection of the book, at the library or bookstore, should suffice.