I currently work at the Centre for Appropriate Technology in Alice Springs, Australia. In the past few months the Dept of Educ and Training has in rolled out a satellite broadband based School of the Air network to remote communities. I have seem a couple of the system and the uptake of them is impressive. However, the equipment has been parachuted in with very little support. The computers are in unlined, unairconditioned building, very much exposed to humidity and dust. Whilst, I realise this is a bad combination, it is not likely to change too quickly.

Can anyone out there suggest some practical ways of maintaining these computers given the environmental conditions?

Alyson! I sympathise with you after living in the bush for years in the same Tropic of Capricorn but obviously in a differen country :D . May I just suggest a few mabe helpful guides. Firstly we can assume you have power either supplied or Genny. Use external fans for cooling if available and remember plastic sheeting attracts moisture, only cover the machines with it after first covering with cotton covers and spacers to keep the plastic clear of everything and then only if realy necersary. There is one known Member here from Down Under who can mabe help and I am sure he will contact you soon. Your message has been on the boards for a while and basically I have replied to just let you know you have not been forgotten and A BIG WELCOME FROM US ALL FROM UP HERE ;)

Stefanus

If they are in a really dusty environment then putting filters on the intake fans (and installing intake fans if they don't have them) would probably be a good idea.

Since there's no air-con I agree with stefanus about having external fans handy, and you would probably wan't to keep an eye on system temperatures for a while to make sure they don't peak too high for comfort.
If CPU temperatures regularly get above 60-70 degrees (that's getting uncomfortably close to CPU death) you might even have to look at third party cooling solutions, which can unfortunately void any warranty if any of these machines have one.

Can't suggest anything for the humidity, Tassie being slightly more temperate :p, humidity's not regularly a big problem.