I've been using outliners since ThinkTank in 1986 on my MacPlus. My next favorite was Acta. Then In Control. I've got a great outliner for my Zire 72 - Shadow Plan. I've got a wealth of outlining power on my Mac - OmniOutliner, AquaMinds NoteTaker, Circus Ponies NoteBook and Tinderbox.
Shadow Plan has a desktop version in Beta for Mac but it's taking a long while to get to anything like stability and it's not very Mac-like. I was poking around to see if I could find a way to move outlines from Mac to Palm and found this goldmine of information in About this Particular Outliner .
I never found my answer. But I believe I've found the best current source of information about Mac outliners on the planet. It's this ATPO column by Ted Goranson on ATPM: About This Particular Macintosh. These are a few of the must reads for Mac Outliner enthusiasts:
Mindmapping Outliners—Aug 2004
Three Topics on the Future of Outlining—Jul 2004
NoteTaker and NoteBook—May 2004This series has appeared almost monthly since September 2003. Ted's articles are in depth, insightful and very readable. I intend to read them all. I'm looking forward to October's in depth look at Tinderbox. Thinking tools fascinate me.