First off, note that the i600 is a Smartphone, so our sister site,
Smartphone Thoughts, might be a better place to post.
Second, you're
supposed to use Wireless Sync with Exchange, not with local PST files. If you're not doing this, you might have some issues.
pdaPhoneHome is another site which has very active forums discussing this situation, and you may find it a useful resource as well.
As for me, I'm running it with no problems with an i700 and XP Pro/Outlook connecting to an Exchange 2003 server.
--janak