Wintec WBT-100
From Wildsong
The Wintec WBT-100 is a GPS receiver with WAAS, bluetooth, USB, a compass, and a datalogger all in one very small package.
I got one 4/12/2007.
You can talk to it with the provided Wintec Windows software. This is my preferred method right now but you can also talk to it with GPSbabel which means Linux or Mac or Windows.
For example you can say
~/bin/gpsbabel -t -w -i wbt -f /dev/ttyUSB0 -o gpx -F buenavista.gpx
For more info see http://www.hexten.net/wiki/index.php/Wintec_GPSBabel_FAQ
For a Ruby version of a program that can talk to a WBT-201, see http://www.daria.co.uk/gps
The reason for using the Wintec software instead of gpsbabel is that it can clear out old logs and it can change system settings; for example it can change the mode used to log.