I just received a Zephyr HRM - a heart rate monitor that sends its data to a PC or smartphone via Bluetooth. It was a reasonable $99 + $30 for FedEx Priority shipping from New Zealand to the States. It shows up as a Bluetooth serial port after pairing with a PC so it makes it very easy to development a .NET application for it. I've currently got code running to talk to the device, verify the integrity of the data packet (CRC) and update new heartbeat timestamps. I'll be using it to track my workouts at home. I may even get adventurous and try to write an app for my WinMo HTC Touch Pro phone, but that will be some time in the future.