After the mention of a cool 4k descent level at last nights meet I went looking and found:
http://www.icculus.org/d2x/
I've not tried it yet but...
Have fun,
Duncan
--
Duncan John Fyfe X-ray Astronomy Group,
Dept. of Physics & Astronomy,
Phone +44 116 252 3635 University of Leicester,
E-mail djf@star.le.ac.uk University Road,
Leicester, LE1 7RH, U.K.