As a Palm user I've been jealous ever since Missing Sync for Windows Mobile added support for syncing notes from Yojimbo last year. Fortunately, Mark/Space has finally stepped up to the plate and the newly released version 6.0 of Missing Sync for Palm adds Yojimbo syncing as well (Mark/Space's own Notebook and Entourage 2004 are also supported for notes). Other new features include some Treo specific features for importing video as well as the Treo's SMS message history. Also new is video encoding support. All in all this looks like a substantial upgrade for Palm users, particularly those with Treos.
The Missing Sync for Palm OS is $39.95 and an upgrade from the previous version is $24.95.