Starting from version 5.1.16, BlackBerry Desktop Manager features an IP Modem menu that will help you setup your BlackBerry as a wireless modem for your laptop. At the moment 5.1.16 is just a leak, but it should make its way to the official BlackBerry downloads soon enough. Each carrier has a different policy about tethering, so it might be a good idea to check with them before running that bittorrent download…