You can synchronize your Yahoo! PIM data (Address Book, Calendar, Notepad, To-Do List) with the following:

Microsoft Outlook 2000/2002/2003
Outlook Express - 5.5 (on Windows 2000 SP4), 6.0 (on Windows XP)
Palm Desktop 4.01/4.1/4.1.2/4.1.4/6.0.1