July 3-6, 2008 Convergence
Bloomington, MN
Science fiction and fantasy
Guest of Honor: Mercedes Lackey, Larry Dixon, David Weber,

July 3-6, 2008 Westercon
Las Vegas, NV
Science fiction and fantasy
Writer Guest of Honor: Kage Baker

July 4-6, 2008 Inconjunction XXVII
Indianapolis, IN
Science fiction and fantasy
Guest of Honor: John Salvi

July 10-13, 2008 Portus
Dallas, TX
Harry Potter symposium

July 10-13, 2008 SFRA
Lawrence, KS
Science Fiction Research Association
Author Guests: Karen Joy Fowler, Paul Kincaid

July 11-13, 2008 Liberty Con
East Ridge, TN
Science fiction
Literary Guest of Honor: Harry Turtledove

July 11-13, 2008Osfest
Omaha, NE
Science fiction, fantasy and horror
Writer guest of honor: Aaron Hollsten

July 11-13, 2008 Polaris
Toronto, Ontario, Canada
Includes the Constellation Awards: fan awards for excellence in Science fiction
Author Guests of Honor: Jim Butcher, Julie Czerneda, Kelley Armstrong, Tanya Huff, plus other authors and media guests

July 17-20, 2008 Readercon
Burlington, MA
Science fiction
Guests of Honor: Jonathan Lethem and James Patrick Kelly

July 17-20, 2008 Necon
Bristol, RI
Northeastern Writers conference
Author Guests: Charlaine Harris, Michael Marshall Smith, James A Moore

July 18-20, 2008 Lazy Dragon Con
McKinley, TX
Science fiction and fantasy themed party con

July 18-20, 2008 Vidcon
Tampa, FL
A convention devoted to fan fiction
Many media and author guests

July 24-27, 2008 Dum Dum
Waterloo, IA
Edgar Rice Burroughs con

July 24-27, 2008 ComicCon
San Diego, CA
Comics
There is a HUGE list of guests, including Ray Bradbury, Jim Butcher and Robert J Sawyer

July 25-27, 2008 Conestoga
Tulsa, OK
Science fiction and fantasy
Guest of Honor: Diana Gabaldon
Toastmaster: Gordon Van Gelder

July 25-27, 2008
Ann Arbor, MI
A "relaxicon", meaning no programming or guests, just partying

July 25-28, 2008 Confluence
Pittsburgh, PA
Science fiction and fantasy in art and literature
Guest of Honor: Joe Haldeman

July 31- August 2, 2008 Pulpcon
Dayton, OH
Pulp science fiction
Guests of Honor:Jerry E. Pournelle and Larry Niven