Slightly off-topic - PDA to use with Mac OS X

Hi all,

This slightly off-topic, but I need some recommendations for a new PDA.

I've been using a Palm PDA for many years, but the Mac version of Palm Desktop does not allow you to use a password for access to private files, so although they are hidden on my PDA itself, they are visible to anyone who gets hold of my MBP!

Can I get some recommendations for a PDA that works with Mac OS X, but where the desktop application, or parts of it, can be secured?

Thanks,

Nige