ok i want to post this to help other members who haven't purchase the Tether app yet..
there are ways to configure your laptop.. and yes even a macbook PRO ( i'm using one right now) to talk to your blackberry and use it as a modem.
and with OS 6 my experience has always been good.
i use a Torch and an early 2008 Macbook Pro Penryn edition.
and i have unlimited data plan with AT&T and not paying anything extra for the tethering.
as i've said.. do a simple search... tether + blackberry and your OS ( say Leopard or OS X) and you will get a step by step instructions on how to tether..
BEST thing is.. it's FREE.