Around a week ago, I tried to get a RHT03 sensor to work with my JeeNode which runs at 3.3V.
Whatever i did, it always returned a timeout error. The datasheet specifies the sensor to work from 3.3 to 6V, so it should work. If i connect 5V to VCC, it worked fine , but not with 3.3V.
At the end i found out that i can connect Pin 3 and 4 (the two pins on the right when looking from the front) to make it work with 3.3V. Pin 3 id NULL, and pin 4 is GND.