UPDATE: Typewriter effects in After Effects at PVC (August 2013) updates the status of Right-to-Left writing systems like Arabic and Hebrew.
Saqib Naqvi shows off many tips for Accessing “Right To Left” Languages Within After Effects, a video tutorial at AEtuts:
'Right to left languages are widely used in After Effects, but traditionally these languages are not treated like text in After Effects. We have to instead covert them to vector graphics which limit many possibilities that are only possible with text layers. In this Quick Tip we will learn to enable languages and manipulate “RTL” text right within After Effects [and Photoshop and Illustrator].'
Simpler but limited solutions might be had by using After Effects scripts from AE Scripts: TextReverser (which reverses the direction of selected text layer), ArabicText (which maintains the integrity of Arabic medial letteforms), and RTL Animation Preset Typewriter-RTL. Hebrew users might look at this tutorial from Eran Stern for an alternate way to enter Hebrew into After Effects.
By the way, check out DecomposeText from AE Scripts, which breaks up text by character, word, or line into separate layers.