DHT22 + Arduino
I recently purchased a DHT22 (Also known as RHT03 on Sparkfun) from Proto-Pic temp and humidity sensor with the aim of using it as an outdoor sensor in the garden. Although there are several DHT22 libraries on github I couldn't get the nethoncho one (or the patched forks) to return anything other than checksum error.
However the combined dht11/22 one I found linked on arduino.cc seems to work just fine. Need to test with -ve temps next but an overnight plot on the bench seems reasonable