Why do I love Web 2.0 / Social Networking / Open Information Sharing? Conference information is really available for download.
Five years or so ago, you had to attend the conference to get the benefit, then the Powerpoints were available, then the audio was available, and now, many of the best conferences provide an online video of the conference, whether you attended or not.
Some of the best 'conferences that share' I have found are:
Web 2.0 Summit
The worst of the conferences is Mobile Internet World, even as an attendee or Platinum Sponsor, the DVD is $999. Boo!
For the record, I attend 15 or so conferences a year, and there is no substitute for the social interaction BUT if you can't attend, this is the next best thing.