The marketshare winner is MsOutlook.
The open-source challenger is Evolution.
Failed hopeful: OSAF/Chandler.
Remember that Software Does Not Manage.
Maybe this should be Personal Knowledge Management.
Why do you need a fancy db-oriented software app at all?
Or, at the next level up, since most email apps have an address book, why not use wiki for just calendar items (and tasks, which few people use), and leave the rest in email?
Or just use the desktop companion software that comes with your PDA, plus an email client.
for calendars, if you're working in a company, you want a system for scheduling meetings where you can see other attendees' availability before setting the meeting time (Group Calendaring)
may want to run on non-standard OS (which could conflict with previous desire)
Running Mini Ruby Wiki for Wiki As PIM on the Sharp Zaurus. --2003/10/31 00:37 GMT
The blog entry at http://radio.weblogs.com/0122027/2003/10/22.html#a92 describes using Mini Ruby Wiki as Wiki As PIM on the Sharp Zaurus.