Scott,
Talk to the pilots on the ground first. Tell them you'd like to try and join
up. Enter the gaggle in the direction that has been established. Stay in a
position that allows you to see the other gliders and have them see you. Try
not to get directly beneath someone, in case they goof and stall....

It's alot of fun once you get to know and trust the other pilots you're sharing
the thermal with.

Of course if they're snobs and are yelling at you already, you may want to
gaggle with some Hawks instead!

Douglas