E! Online have the draft schedule of TV-related Comic-Con events, according to which Supernatural panel will be held on Sunday, July 26, 11:45 a.m.-12:45 p.m.
The 2009 San Diego Comic Con will take place July 22-26 at San Diego Convention Center, 111 W. Harbor Drive, San Diego, California, USA.
Please note that no offical word has been given. The complete Programming schedule will be posted on the Comic Con site about ten days to two weeks prior to the show.
Source: E! Online, 2009 San Diego Comic Con.