I've used the Spb Full Screen Keyboard for Pocket PC, and it works well, for what it is. It's very responsive, and you can get some good speeds on it. There's a small single line of text visible while you're using it... I would choose this as a model over Dialkeys, just because Dialkeys is meant for a larger device. Just an idea.

http://www.spbsoftwarehouse.com/products/fsk/?en