Based on the Marvel Previews #82, June for August 2010, I'd say you need to pre-order the following books in order to keep up with Spider-Man.
Core Titles
Amazing Spider-Man #640
Amazing Spider-Man #640, sketch cover by Quesada
Amazing Spider-Man #640, variant cover by Quesada
Amazing Spider-Man #640, Women Of Marvel variant
Amazing Spider-Man #641
Amazing Spider-Man #641, sketch cover by Quesada
Amazing Spider-Man #641, variant cover by Quesada
Amazing Spider-Man #641, Women Of Marvel frame variant
Spectacular Spider-Girl #4
Spider-Girl: The End #1
Spider-Man / Fantastic Four #2
Spider-Man, Marvel Adventures #5
Ultimate Spider-Man #13
Web Of Spider-Man #11
Guest Apps
Amazing Spider-Man Presents: American Son #4
Amazing Spider-Man Presents: Black Cat #3
Avengers & The Infinity Gauntlet #1
Avengers #4, regular cover
Avengers #4, variant cover
Avengers #4, women of marvel frame variant
Marvel Universe Vs. The Punisher #1
Shadowland #2
Shadowland #2, evil daredevil variant cover
Ultimate Mystery #2
Reprints
Civil War: Spider-Man HC
Spider-Man: The Complete Clone Saga Epic Book 3 TPB
Strange Tales TPB
Ultimate Spider-Man Ultimate Collection Book 3 TPB
Women Of Marvel: Celebration Seven Decades Omnibus HC
Women Of Marvel: Celebration Seven Decades Omnibus HC, variant edition