all you need is a Arduino with an Ethernet shield and some LM35´s:
The connection on the Watercooler:
a LM35 with a cabletie mounted to the metall connector, thermal coupled with some heat conductive paste.
Then let it post to Pachube.com and it works
The Thread in the Arduino Forum: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1240340386
The Thread in the Pachube Forum: http://community.pachube.com/node/191