I've loved using the GoPro HD Hero to capture my rides, however, there's one area where the GoPro falls short. It captures mono sound. The three dimensional realism of stereo sound is absent standard in the device! I've been looking for an inexpensive solution for this and found a WOOT.com sellout for the SANYO Xacti ICR-XPS01M Digital Sound Recorder.
It's a stereo PCM or MP3 capture device that will allow me to add stereo sound to my video captures. It's straightforward to use, records for many hours on the included 2GB microSDHC and most importantly, captures high quality stereo sound!
Here's a shot of how small this device is. I've got a life-size paper cutout of it sitting beside my GoPro HD Hero. The trick now is to mount them together so that I can synchronize them fairly easily. I know to record a hand clap at the beginning of the recording so that I can visually line them up...