Based on the Marvel Previews #69, July for September 2009, I'd say you need to pre-order the following books in order to keep up with Spider-Man.
Core Titles
Amazing Spider-Man #604
Amazing Spider-Man #605
Amazing Spider-Man #606
Amazing Spider-Man #607
Marvel Adventures Spider-Man #55
Marvel Zombies Return: Spider-Man
Marvel Zombies Return: Spider-Man, variant cover
New Avengers #57
Spider-Man: The Clone Saga #1
Ultimate Comics Spider-Man #2
Guest Apps
Dark Reign: The List - Avengers
Dark Reign: The Sinister Spider-Man #4
Official Index To The Marvel Universe #9
Punisher Annual #1
Strange Tales #1
Reprints
Spider-Man Magazine #8
Spider-Man: Noir TPB
Thor By Dan Jurgens & John Romita Jr. Vol. 1 TPB
Ultimatum Premiere HC
Ultimatum: Requiem Premiere HC
Ultimatum: Spider-Man Premiere HC
Spin-Offs
Amazing Spider-Man Presents: Anti-Venom - New Ways To Live #1