The Sprint Treo 650 is… notable for what it does not include: dial-up networking (or DUN) over Bluetooth. Fortunately, a skilled Treo 650 user (known only as shadowmite) spent several hours tracing code and discovered that Sprint had not removed DUN; they had merely hidden it. A two-byte change in the Treo’s Bluetooth management code reveals the hidden setting. Trevor Harmon has posted step by step for setting up dial-up networking with the Sprint Treo 650 smartphone using Bluetooth and Mac OS X. [via] Link.
Use a Treo 650 with Mac OS X