MacInTouch Home Page: "... Palm Converter 2.0.0a1 is an application that can read some of the files created on a Palm and transferred to your desktop when you HotSync, including MemoDB, Memo32DB, MobileDB, and other database files. This alpha release is a complete rewrite of the program to allow for expansion of translators. It also now exports to XML and exports ThoughtManager outlines to OPML. Palm Converter is free for Mac OS X and Mac OS 9."
This site also offers JFile Companion, a Mac product for manipulating PalmOS JFile databases.