I'm planning on going (the convention is held on the 22nd and 23rd of January, 2010), but I don't have anyone to go with me! Mr. Shatner and the venerable Mr. Stewart will be there on Sunday (which is when I'm going).
Tickets are kind of expensive but I'm sure it's worth it. It's like the Star Trek equivalent of Wondercon, which is the smaller, Norcal version of Comiccon.
More info on the official page: http://www.creationent.com/cal/stsan.htm