What's your favorite book or resource for social media marketing?

I learned quite a bit of relevant information in reading David Meerman Scott's excellent book, "The New Rules of Marketing and PR" I'm looking for similar focused, tactical, and useful resources to help in developing and executing the marketing and launch strategies for a new user generated content web site.

What are your suggestions?

Thanks.

To the point the obvious: Dharmesh's very own Inbound Marketing: Get Found Using Google, Social Media, and Blogs (The New Rules of Social Media)

The Social Media Marketing Blog

You might want to look at "The Whuffie Factor" by Tara Hunt. Somewhat generic but good food for thought on how to go about utilizing social media for your business.

Engage, by Biran Solis is considered an industry standard. - http://www.briansolis.com/2010/01/engage/

Podcasts from iTunes on this very subject. Some excellent material available that I can listen to on my daily travels.

I find myself not having much time to read the traditional books... so I resort a lot to online information (which also tends to be more updated, since it covers what's happening THIS minute).

A great place to go get ideas and learn is Marketing Profs. They have a ton of stuff about inbound marketing, PR, social media, lead generation...

Hope this helps