Here is what my Intellisync help says (I have an MSN account):
a.. To use Intellisync, you must subscribe to MSN or have been added as a
member on the primary user's account.
b.. Intellisync, MSN, and the program you are synchronizing with must be
installed on the same computer.
c.. Install the program you want to synchronize with before running
Intellisync Setup. Intellisync only provides setup options for programs it
can detect. For example, if you want to synchronize with a Pocket PC,
Microsoft ActiveSync must be installed on your computer before you run
Intellisync Setup.
d.. You must be connected to the Internet during Intellisync Setup and
when synchronizing. Intellisync synchronizes with MSN servers, so it must
have access to them through the Internet.
e.. While synchronizing, Microsoft Outlook can be open or closed.
f.. While synchronizing, Palm Desktop must be closed. It does not matter
if your Palm Pilot handheld device is in its cradle.
g.. While synchronizing, Microsoft ActiveSync can be open or closed. Your
Pocket PC must be in its cradle.
System Requirements
Use Intellisync to synchronize MSN Calendar and Address Book with one or
more of the following programs or devices:
a.. Microsoft Outlook versions 97, 98, 2000, or 2002 (XP).
b.. Pocket PCs running Windows CE Services 2.0 or later. You must have
Microsoft ActiveSync version 3.1 or 3.5 installed on your computer.
c.. Palm Pilot handheld devices. Palm Desktop versions 3.1, 4.01, or 4.1
must be installed on your computer.