St. Clair Software has released Jettison 1.2, an update to their application that automatically ejects external drives before your Mac goes to sleep. The upgrade allows you to choose which types of drives it ejects, and automatically remounts any drives that are still connected when you reawaken your Mac.
Jettison is designed to eliminate the hassle of manually ejecting Time Machine backup drives, network server volumes and flash drives. Just close the lid of your MacBook, and Jettison does it for you.
Jettison requires Mac OS X 10.6 or higher. Version 1.2 is a free update if you purchased an earlier version. It’s available for US$1.99 for new users in the Mac App Store.