Earlier on Searchenginewatch.com they were plugging www.ecomxpo.com because there is a free conference being hosted there from April 4th through April 6th. It's all on the web through a Macromedia plugin and meeting organizer, and seems very similar to what SES was except with a few less sessions.
The main name I noticed was Christine Churchill, and the three keynote speakers are Bryan Eisenberg (author of "Call to Action", Anne Holland (MarketingSherpa President), and Geoff Ramsey (CEO of eMarketer)
I've signed up, just wanted to let you guys know about it.