According to this post over on the C7Y site (php|architect's community site), their php|tek 2008 conference has already reached the forty percent sold mark on seats for the event.

Seat sales for our php|tek 2008 conference, which will take place in Chicago, IL, between May 20th and 23rd, are starting to pick up, and over 40% of all available spots have already been reserved.

You can signup on their conference website as well as get all of the details on the four day event including the speaker schedule, hotel and travel information - even a Boss Help section to help with convincing your local PHB.