I've started adding projects and tasks at https://sourceforge.net/pm/?group_id=6616 -- Feel free to sign up and start working.
We're off the ground! Not very high, but it qualifies as airborne in my book. Have a look at the introductory materials at http://plnet.sourceforge.net. Very soon we'll get a task list posted, so everyone with who has spare time this summer will have plenty of ways to help out!