As a Palm OS developer, I've accumulated a number of devices over the last few years, including several that support Bluetooth. When I last looked, I had four different BT-enabled devices in my personal inventory, and I expect that number to grow as more of the licensees produce hardware with this useful wireless technology. Bluetooth looks like it will get a good boost with Windows XP Service Pack 2, which will ship with Microsoft's own BT profiles.
Unfortunately, there's a snag coming with Bluetooth and Palm OS devices relating to the set of profiles supported by the Palm OS BT stack. The Bluetooth standards define a set of service profiles that define connections between Bluetooth devices. For Internet access, Palm OS currently supports the Dial up Networking Profile (DNP) and the LAN Access Profile (LAP). However, many new Bluetooth devices and access points don't support LAP; they support a newer profile called Personal Access Network Profile (PAN). Technically, LAP was a one-on-one connection between the device and a server, similar to PPP, while PAN is more like Bluetooth Ethernet, with all the devices in a local Piconet able to directly access each other, and the router acting like a gateway to tunnel packets to a wired LAN.
I was alerted to this when I was looking for BT access points. There's a popular unit by Cadmus that's showing up on eBay a lot; unfortunately, it's a PAN-only access point, so it can't be used with current Palm OS devices. I know people have had good luck with access points from Pico Communications and Belkin. I'm worried about some of the comments I've seen about Windows XP SP2's Bluetooth; it looks like it only has the PAN profile, although it may be possible to use Dial-up Networking to get a PPP connection over RFComm, allowing you to continue to be connected.
For more on Bluetooth, I highly recommend Peter Easton's site, www.whizoo.com. He has a some very useful sample code and utilities. For more on supported Bluetooth profiles, there's PalmSource KB article 382.