Looks like you can go to City Hall Council Chamber (?) or attend the webcast.
They have a gigantic speakers list, including Ken Cochrane, Chief Information Officer (CIO) for the Government of Canada and Peter Cowan, Director of Enterprise Information Management at Natural Resources Canada (NRCan).
The site says
City of Toronto Web 2.0 Summit will be an exciting, interactive forum to explore how Web 2.0 technology can change the way governments interact with citizens, create policies and make decisions.
City of Toronto - Moving Toward Government 2.0 - Web 2.0 Summit
via Michael Neilson in FriendFeed