Here you’ll find some hints where to find more information on how to use your Bluetooth mobile phone as a remote control and a GPRS modem for your Mac.
Mobile phone as remote control
To use your mobile phone as a remote control for programs like DVD Player, VLC, Keynote, or PowerPoint, there are two main programs that help you doing so: the freeware Romeo and the Shareware SallingClicker.
Both applications support AppleScript and proximity modes and come with already pre-installed plugins for several programs.
Mobile phone as GPRS modem
A description on how to connect to the Internet using a Bluetooth mobile phone as a GPRS modem can be found in the book Mac OS X Hacks by O’Reilly.
The biggest challenge in setting up the whole thing is to find an appropriate modem script. If the scripts mentioned in the book don’t work properly for you, try the free-of-charge scripts published by Ross Barkman.