Since we are in Clearstep, I imagine your reference to "Web 2.0" means social/community programs on the web...
I attended the "Communities Exchange" conference late last year, and it was a great primer for me. A lot of industry leaders in enterprise/B2B communities were there (Intel, Dell, EMC, Microsoft, Oracle to name a few), and there was plenty of time to sit down and talk with these folks face-to-face and ask questions.
Unfortunately, I was the youngest person there (25), so I became the "token millenial/digital native" during the conference and was grilled during the Q&A portion.
Not sure if they're doing it again, but I think it's a great introduction to the Community space.
I attended Web 2.0 in NY last year and enjoyed it. Since I am focussed on an internal community, however, it wasn't directly targeted to my needs but I still got value from it. I am looking forward to attending the Enterprise 2.0 conference this year.
Full disclosure: my company produces both of these conferences
Forum One is hosting the Online Community Business Fourm 2009 in Sonoma, California on March 19-20 which should be a good one to attend.
Hope this helps!