If I'm going to wireless tehter to my Android phone what method drains the battery the least? Wifi or Bluetooth?
I decided to look up some data, and my guess seems to be correct: http://nesl.ee.ucla.edu/fw/documents/reports/2007/PowerAnalysis.pdf
According to the report, Bluetooth takes the least amount of energy.
However your 3G radio will probably take the most energy; maintaining a 3G connection without transferring any data is cheap, but once you start sending/receiving data, then it trumps even Wi-fi.
WiFi radios have a high wakeup and connection maintenance energy, but low energy per bit transmission cost and high bandwidth.
Cellular radios have low connection maintenance energy, but high energy per bit transmission cost and low bandwidth.
Disclaimer: The study might only apply for the particular model that the device they use.