Stan Lee, the co-writer of the manga series Ultimo will be at  the Rock’n Comic-Con 2010 in Los Angeles, CA this Saturday.  The location is the Pasadena Convention Center (300 East Green Street), Booth 402 from 2-3PM on May 29th. Volumes of Ultimo can be purchased on the spot for $9.99 (no tax). This convention is not to be consfused with the San Diego Comic-Con (July 22-25th, 2010).

Source: http://www.mania.com/stan-lee-signing-ultimo-this-weekend_article_122883.html
Additional info: http://www.rockncomiccon.com/