I found my Holy priest missing when Surge of Light procced and so I took the mod "Night_Warner" by Xerogen and modified it to display the surge of light icon and a little message when it procs.
Now I never miss my free smite.
Use /solshow to show the frame and reposition it for when it procs. I like the middle of the screen.
Use /solhide to dismiss the frame once you've set its position.
Use /solsound to toggle an audio alert when a proc occurs
v1.3 - Updated TOC for 3.1 compatibility.
v1.2b - Fixed typo that was causing issues in the last version. WotLK compatible.
v1.2 - Updated code for 2.4 combat log changes
v1.1b - Fixed bug that meant the alert was not hidden when proc ended
v1.1 - Tidied up display font, added fading frame and audio alert
v1.0 - Initial release