The official Star Wars site has a summary of activities for the Celebration 2 convention and Concept Artist Iain McCaig will make two appearances. Also the TheForce.net is reporting that there will be a special DVD on sale with an interview with the original Star Wars Concept Artists, Ralph McQuarrie.
Iain McCaig will have drawing classes for adults and kids and will also talk about the costume design for the film alongside Concept Artist Dermot Power and Costume Supervisor Trisha Biggar. Ralph McQuarrie's DVD will be on sale at his website after the event.
Here are the handy links: