I just installed a new sim. It is named CONDOR.
I believe is the best soaring simulator I ever tried.
From my (limited) experience in a glider (the real life stuff) this is really amazing.
More news about this sim here:
http://www.fspilotshop.com/product_info.php?products_id=438
http://www.flightsim.com/cgi/kds?$=main/notams05/cond1214.htm
You can fly both offline or having online competition. My experience is limited to offline for the time being, with a total of about 10 hrs flying.
I never thought before that flying without combat could be so exciting.
Moreover it is a great help in order to develop the flying instrument confidence and usage (variometer, speed, compass, ball) and the ability of being careful in the stick and rudder usage. Remember you are on a glider, you do not have any engine, and your optimum speed is 90 Km/h.
Great fun, really! 