The ClieSource Forums are an excellent source of info. It turns out that installing the movierecorder.prc (version 1.3) from a UX50 onto the TH55 allows it to record movies. The problem is getting that file….
Here’s the trick: you can’t just install the app via Palm Sync. You’ll have to copy or sync it onto the Memory Stick, then copy it to the internal storage. Happy video!
[UPDATE]: I found more info and a better source for the movie recorder here.
For example movies shot using the Clie TH55, follow the links in this story about Cliff’s Piranha.