IIRC MobiPocket files are just raw HTML in PDB form. I might be wrong.

http://www.palmblvd.com/software/pc/...2-palm-pc.html

Should convert from MobiPocket to plain old HTML: you can either view it using the built-in browser, or install FBReader.

Since FBReader can handle HTML that's in ZIP files (saving quite a bit of space) I'd recommend it: it's also much better for reading long documents.