Union Pearson Express Rail Link Info?

Just wondering if anyone here has any concrete info on the Pearson Airport-Union Station rail link? I'm wondering on which side of the airport it would connect to. Would it connect to the Malton GO line, or the Islington subway line? Or something else? Has this stuff even been decided yet? 2015 (when the Pan Am Games arrive) isn't all that far away.

All you need to know about this project is available here: http://www.gotransit.com/gts/en/default.aspx

The thread for this topic is located here:

http://urbantoronto.ca/showthread.php?3188-Georgetown-South-Airport-Rail-Link-Project

If you have any further questions (after looking at RR's link), I'm sure someone will be happy to help out.