Motionworks has a new After Effects tutorial, After Effects: Creating magic from presets – part 1:
"In this two-part tutorial learn how to take basic Adobe After Effects presets and customise them to create your own unique looks. This section focusses on giving a simple text preset a touch-of-class, with a clear explanation of Text Animator Groups, Animator Properties and Range Selectors. Turning a simple typewriter look into something much more special. "
There's more in AEP's AE presets & projects round-up and in AE Help. Here's a Focal Press overview of presets from Chris Meyer:
Update: part 2 of the Motionworks tutorial is up, plus AE Help has more in Examples and resources for text animation.
Update: Rhys-works has an expressions tutorial that creates a typewriter style effect and Example: Create a write-on animation in AE Help shows something similar.