FastMac announced the immediate availability of an internal Bluetooth upgrade for the PowerPC-based Mac mini on Monday. The upgrade lets you add Bluetooth to your Mac mini and still be able to add AirPort Extreme support later. Since the upgrade goes inside of your Mac, your USB and FireWire ports are left open for other devices.
FastMacis Mac mini Bluetooth Module Upgrade.
The Mac mini Bluetooth Module Upgrade kit is priced at US$49.95. An 802.11b/g add-on card costs an additional $49.95.