I use ShapeWriter on my MotoDroid and love it.
I recommended it to a friend who just got an Incredible today and helped him download it. Went into settings and told "Language & Keyboard" to use it via a checkmark. Unfortunately, it didn't replace the original keyboard and I can't figure out how to replace the original keyboard. Wasn't a problem like this on my MotoDroid.
Any ideas where I go next to try to get it to work?