Price: Free (basic version), $1.49 (Pro version)

App 2 SD analyzes your installed apps and conveniently lists those that can be moved to your SD card, those already on the SD card and those that can't be moved from internal storage. Then it helps you move all appropriate apps to the SD card (either individually or as a group) to free up internal storage space. It can also monitor new apps you install in the future and notify you when they're movable.

The lists of apps are by default sorted by their file size, so you can quickly see those that are taking up the most space. Total space and free space of your device's internal storage and SD card are conveniently shown on the bottom of the app. App 2 SD also has a simple cache-clearing feature that prompts you to clear app cache if it's larger than 500KB.

Unfortunately, App 2 SD can't automatically move the apps to the SD card. It can only pop up the Application Info screen for each app you want to move; you must then manually hit the "Move to SD card" button, and (if moving multiple apps) then hit the back button to go to the next Application Info screen.

If your device is rooted, consider using instead of (or in addition to) App 2 SD, which can automatically list and move apps -- it doesn't, however, automatically notify you after installing a movable app like App 2 SD does.