I don't know about
Jet Set Willy or
Sabre Wulf, but a
Java emulation of
Sandy White's
Ant Attack is available on the
author's own
webpage, http://www.sandywhite.co.uk/, along with a wealth of
information about the game. I therefore assume that the game has now been placed into the
public domain and so posting it here would not in fact be
violating anyone's
copyright.
It would still be a pretty stupid thing to do, however.