Hello there, I'm the author of this page:
Tethering With Blackberry Pearl On Linux [Thibaut Colar's Home]
Which explains how to tether using barry & XMBlackberry (back then anyhow)

This is a bit obsolete and complicated, so i made a new tool which only goal is tethering with a Blackberry.

It's much easier to install since it's just a python script (few dependencies).

See here for Instructions:
BBTether - Easy Tethering for Blackberry on Linux [Thibaut Colar's Home]

I only have a Pearl and tmobile so that's all I've tested it with so far, it's brand new so probably buggy, but I would love it if other people used it and gave me feedback so i can improve it.

Please let me know how it goes and success/failue stories at tcolar AT colar dot NET

Thank you.

Just wanted to add that it can also put your BlackBerry in charge mode (USB)

Just rebuilt it (now version 0.1b) as i had a bug in previous one which wold cause ppp to disconnect right after connecting.
Works good now.

Unfortunately, I have a password protected device and your tool has no support for that. Will you be looking into password support?

I have an AT&T Bold on a BES...

I made a new version that works way better now.

As for password support, not yet but that's probably my next task now that i finally got a stable connection as fast as i can make it.

does this only work for linux, or will it also work for windows?

The latest version (0.2g) should work with password protected devices. (let me know).

It's for linux (or other Unixe's including OS X).

As for windows i suppose it could work, you would have to install libusb, python, etc... but i'm not sure what the point would be, since you can use the official Blackbery Application (BB Desktop manager) on windows.