After Effects provides a vast array of capabilities for effective and creative 2D and 3D text animation. The resource and examples you'll find here provide detailed instructions on how to animate your text in After Effects.
Harry Frank provides a tutorial on animating text with text animators on the Digital Arts Online website.
Steve Holmes provides a tutorial on the Layers Magazine website that uses three text animators and per-character 3D text animation to create a text animation.
Colin Braley provides a tutorial and example project on his website that show how to use an expression on the Source Text property to animate text to overcome some of the limitations of the Numbers effect.
Eran Stern provides a video tutorial on the Creative COW website that demonstrates how to use per-character 3D text animation to animate text along a path in the shape of a 3D tornado.
Angie Taylor provides a tutorial on the Digital Arts website that shows how to use per-character 3D text animation together with a common workaround for simulating extruded 3D text.
Eran Stern provides a video tutorial on the Artbeats website that shows how to use the After Effects text animation system as a particle system.
Rich Young collects several resources and tutorials for creating extruded 3D text in After Effects.
On the ProVideo Coalition website, Chris & Trish Meyer provide several tips for animating text in After Effects.
Toby Pitman shows tricks for using shape layers to animate text on the MacProVideo website.
This example illustrates how you can easily animate individual characters in 3D so that each character steps out of line and takes a bow.
This example illustrates how you can easily animate random characters so that they gradually form a legible word or phrase by specifying a Character Offset value and animating the range selector.
This example demonstrates how easy it is to animate the position of individual characters. It also shows how the Wiggly selector can create a dramatic change to the animation simply by adding it to the layer.
This example shows you how easy it is to isolate characters when tracking a line of text. Using the Tracking and Line Anchor animator properties, you can easily move all but one or a few characters.
You can easily create the appearance of writing on the screen by using the Opacity animator property.
This example uses the selectorValue parameter in an Expression selector with the Wiggly selector to make a string of characters flash on and off randomly.
This example uses the textIndex and textTotal attributes with the wiggle expression to animate a line of text.
With no layers selected in the Timeline panel, double-click the Current Time Format animation preset in the Effects & Presets panel. (You can locate the animation preset by typing its name in the Contains field in the Effects & Presets panel.)
A new text layer is created, with an expression on the Source Text property that makes the text show the current time in the time display format set for the project.
You can use other expressions in the Global category to display time in another format.
To see the expressions on a layer, select the layer and press EE.