I use a digital camera and take 12 pics that are stitched together.
The sphericals are done by The Ragged Rascals and they use an 8mm lens. 3 shots make a whole spherical. Very neat eh?
Check out http://www.users.myisp.co.uk/~gtour/CdRom.html
if you want to see lots more of avebury etc
PeteG