Free and ad-free.
Can turn on/off, set duration of the flash, number of times it blinks, and whether or not to only flash when screen is off.
Very small, simple, lightweight.
Probably won''t work on Galaxy Nexus and some LG and Motorola devices because of weird device-related restrictions.
**IMPORTANT FOR GO-SMS / HANDCENT USERS**
To work for Go-SMS:
- GoSMS → Settings → Advanced Tab → Other Settings → uncheck "Disable other message notification"
See screenshot: http://i.imgur.com/AJNM7aE.png
To work for Handcent:
- Handcent → Settings → Application Settings → Default Messaging application -> Disable.
See screenshot: http://i.imgur.com/ihIW4Nx.png
You might also have to manually disable notifications in the default messaging app if you''re using either of the two to prevent double notifications, by opening it, pressing Menu → Settings, and unchecking Notifications.
See screenshot: http://i.imgur.com/bFlVsIi.png