Since RIM OS4, it has been possible to use a Blackberry as tethered modem with a notebook computer, allowing your notebook to connect to the internet anywhere your phone can.

Read all about it in this Blackberry forums article on how to use a Blackberry as a modem for a laptop.

I got this working successfully on my T-mobile 7290; be sure to have your phone plugged in and run the Blackberry Device Manager software before you try testing or using the connection. Naturally, no one would mistake GPRS for broadband, but the connection is fine for emailing, blogging, and light web browsing. (I’m posting this message through my phone connection.) Very cool.

Note that this approach requires a PC and a USB connection. There are also Bluetooth alternatives.

Bluetooth support for PCs:: Mobishark supports Bluetooth modem functionality for PCs and the Blackberry. See Blackberry forums for details. Mobishark is $45 and supports a free trial.

Bluetooth support for Mac OSX: Pulse supports Bluetooth access to the Blackberry on the Mac. Pulse is $50 and also supports a free trial.
. Or if you’d like a free option, try the OSX modem script from fibble.org; it sounds like this hasn’t been tested on as many different devices but the price is certainly attractive.