My best results were with Comfile CUBLOC that has two USARTS, one for monitoring the system, the other for serial-to-Ethernet. But wait, now you can get the Arduino/Wiring Board-esque Sanguino with 2 USARTS. The Sanguino (no USB) is around $30, the Wiring Board itself is $60 if you need a lot of digi I/O.
Then I come upon a new Wind Sensor from Modern Device. The anemometer impeller solution was always kind of expensive plus it took a long time to spin down once spun up. I wonder how responsive this one is? At $17, it is also way cheaper.