I have an Air Canada Aeroplan account with zero miles in it. I use it only for checking award availability — Air Canada lets you search awards on all of its Star Alliance partners. Then I claim the awards with United or USAirways miles.
I just noticed that ANA now offers Star Alliance award searches (login required) and their tool, though a bit more complicated, also seems more powerful. I’ll be testing it today.
A big thumbs up to both Air Canada and ANA for offering powerful award search tools online — as far as I can tell, well ahead of any other airlines in any global alliance.