I’ve had a great deal of success with Cocoa UltraSMS lately. Unlike SMSLib (the java library I’ve been using) this library responds correctly to new message alerts from the phone. So access is immediate. The messages are stored in a MySQL database and are easily accessed with Processing (and any other Java), MaxMSP, PHP, etc.

This little app works really well with OS X. For a Linux, Windows, etc, take a look at the UltraSMS framework.