Based on the Marvel Previews #94, June for August 2011, I'd say you need to pre-order the following books in order to keep up with Spider-Man.
Core Titles
Amazing Spider-Man #667
Amazing Spider-Man #667, FF Anniversary variant cover
Amazing Spider-Man #668
Spider-Man, Marvel Adventures #17
Guest Apps
Avengers #16
Avengers: The Children's Crusade #7
Fear Itself Poster Book
Fear Itself: Fearsome Four #3
FF #8
Marvel Universe Vs. Wolverine #3
New Avengers #15
Spider-Island: Deadly Foes #1
The Marvel Art Of John Romita Jr. HC
Ultimate Fallout #4
Ultimate Fallout #4, Marko Djudjevic variant cover
Ultimate Fallout #5
Ultimate Fallout #5, Marko Djudjevic variant cover
Ultimate Fallout #6
Ultimate Fallout #6, Marko Djudjevic variant cover
X-23 #13
Spin-Offs
Venom #6
Reprints
Amazing Spider-Man: Infested #1
Avengers Academy: Arcade - Death Game TPB
Carnage: Family Feud HC
Deadpool / Amazing Spider-Man / Hulk: Identity Wars Premiere HC
Essential Spider-Man Vol. 1 (All-New Edition) TPB
Essential Spider-Man Vol. 2 (All-New Edition) TPB
Essential Web Of Spider-Man Vol. 1 TPB
Fantastic Four By John Byrne Omnibus Vol. 1 HC
Fantastic Four By John Byrne Omnibus Vol. 1 HC, direct market variant
Green Goblin: A Lighter Shade Of Green TPB
Marvel Adventures Spider-Man: Friendly Neighborhood Digest TPB
Marvel Super Stars Magazine #6
Shadowland: Street Heroes TPB
Spider-Girl: Family Values TPB
Spider-Island: Emergence Of Evil - Jackal & Hobgoblin #1
Spider-Man: The Fantastic Spider-Man Premiere HC
Spider-Man: The Next Chapter Vol. 1 TPB
Spider-Man: With Great Power Comes Great Responsibility #5