pronger
we have done this in Australia and have achieved excellent results
they are several key things to worry about
1) choosing the correct antennae & making sure they are set up right for example making sure they are directional antennae and the distance between buildings does not exceed the capacity of the technology - the distances that you have outlined are OK . Also make sure there is clean line of sight no trees will grow in between the antennae and no buildings will be put between the two sites you are connecting some time down the track.
I have been caught out on these sorts of details in the past
2) 802.1b is OK outdoors but 803.11a is not great outdoors
3) 802.11b has to be made secure - it is not secure out of the box unless you add some of the Cisco security in the switches etc but straight out of the box bridged neworks are not something that you would sell to a Bank or Defence
but a school or a commercial operation should be OK
4) you MUST do a site survey you cannot guess what equipment you need
5) once you establish how many AP's you need then you can order but don't expect to get any more than one or two concurrent users on an AP if you are sending huge amounts of data back and forth between multiple clients and a single server.
6) dont expect to get any more than one third of the bandwidth capacity that the manufacturer claims for example I think 802.11b claims to run at 11mbps thst is unrealistic you will be luck to get 3mbps or 4mbps.
Good Luck
Bob H
Sydney
Australia