Although I’ve never used it, many folks swear by the Fitaly keyboard method of text entry on mobile devices. In speed tests, people have achieved upwards of 50 words per minute using Fitaly, so it clearly has to work if you can get used to a new keyboard layout. Fitaly version 4 includes Windows Mobile 5.0 support as well as additional enhancements over the previous version.
The premise of Fitaly is to minimize the distance between between key "presses" with 73% of the keys most often used in a central area. The new version is free for users of Fitaly 3.5; for new users, the price is $29, but you can download a free, 30-day demo here.
UMPC and Tablet PC owners should take note: there’s also a 32-bit version of Fitaly for Windows that runs on XP as well as older Windows versions. The cost is $39 and might be worth a look if you’re searching for a TIP or Dial Keys replacement. Alas, no free trial available for Windows users. :(
(via Pocket PC Thoughts)