ml> how can one set up their own "shadetree mechanic" type
 ml> of instruments like the wet bulb thermometer? is it
 ml> just a matter of having two thermometers the same and
 ml> mounting out with a cloth that is soaked with water?

Yes.  In this case, two electronic temperature sensors.  A fan is also
required to fully depress the wet bulb reading.

 ml> i've been by several weather related sites looking at
 ml> their machines... we've been wanting to have something
 ml> out here for a long time but the cost has always been
 ml> prohibitive...

I've got a very inexpensive Radio Shack instrument that measures humidity. 
It's very precise, but did require "shade tree mechanic" work to
make it accurate.  I connected a variable resistor in parallel with the
sensor and adjusted it until I got readings that pretty much matched my wet
and dry bulb measurements using a conventional sling psychrometer and
chart.  Finally, I soldered the appropriate-sized resistor in paralllel to
the sensor, put the cover back on it, and mounted it on  the wall.  It's
worked famously for several years now.

I'm THE humidity-measuring guru on campus.

---