as for this latest question, at most airports, you can't just guest anyone in flying any flight on any airline. There are separate terminals, and some require guests to be flying on the airline at issue. You'll just have to spend the 4 minutes to look up what lounges are in the terminal you're flying from in order to mooch off someone else's lounge access.

But there is a calendar on Flyertalk which seems close to what youre asking for: http://www.flyertalk.com/forum/lounge_connect.php