Ever since I got my Google Nexus One, I been using my mobile a lot and no, I don’t make many phone calls. Recently I saw someone else using an Android phone, but using the touchscreen keyboard to find and type one letter at a time. There are various softwares available that will help you type faster but the one that I use is SlideIT from Dasur.
If you are still not sure whether it is for you, check this video. (I can type faster than that guy)
Some of the other options available are:
You can download the demo of SlideIT from Android Market or purchase it from Dasur