Many power users are kind of puzzled by TetherBerry. Tethering your BlackBerry is not that complicated to setup for free using one of the multitude of guides available online. Even RIM provides you with basic instructions on how to set it up and offers the option in Desktop Manager 5.0+. In my opinion TetherBerry is the solution for those who cant be bothered and want paid support for setting it up on their Mac or PC.
If you fall into that category you will be happy to learn that the best selling app TetherBerry is on sale today for $24.97 which is 50% off their uber-expensive $49.95 regular price. TetherBerry does a brilliant job of dumbing down the process of setting up tethering for you BlackBerry so definitely check it out if you are having issues!
Let us know if you pick up a copy and why! Maybe it is about time we created our own guide for setting up tethering easily.
PS: All tethering solutions may end up getting you charged by your carrier if they catch you. Most carriers usually require a tethering add-on to your monthly plan called Phone as a Modem or such. If you get caught you could stand with some serious data overage charges. If you do end up paying for the add-on tethering option then your carrier usually provides you with an application that simplifies this whole process making all of these solutions irrelevant.