[highlife22]

You can try some of these,

http://www.all-at-hand.com/softwaresmspc.php?id=54

http://iwindowsmobile.com/threaded-sms-messaging.html


And theres one called Advanced SMS Corporate, I think the personal version is free if you can google it and find their main website.


Edit: 2 more

http://www.skbsoftwares.com/

http://www.trinketsoftware.com/powersms/ (I like this)