The Treo 700w series phones are equipped with Bluetooth, which allows one to use wireless headsets, but also potentially opens up some vulnerabilities. Informit recently published an article discussing vulnerabilities with Bluetooth devices:
The other major problem with current Bluetooth devices is that some sensitive functionality is exposed to unauthenticated users. When designing a Bluetooth-enabled device, system designers may want to provide certain pieces of functionality to non-trusted users. Unfortunately, sometimes more functionality is exposed than is intended, and attackers can read and/or write information to which they shouldn’t have access. These types of vulnerabilities are device-specific; for instance, cell phones from one manufacture may be vulnerable while those from another are not.
Read the full article at http://www.informit.com/articles/article.asp?p=442341. If you use Bluetooth connections with your Treo, check with Palm to make sure the various vulnerabilities have been patched (remember that new ones may be found also). If you don’t use Bluetooth, turn it off.