The facebook group is here. The specific TSA discussion is both here and on their main group page. There is a slashdot discussion here. Bruce Schneier was scheduled as a witness at this hearing, although he recently cancelled. Committee on Oversight & Government Reform overview of the TSA hearing.
The fact that Congress is using the phrase "Security Theater" is very promising.
Reminder- the site lists each congressperson that is part of this committee, why not contact a committee member directly if you would rather not go through facebook? Especially if they are representing your state.
EDIT: Considering how adhoc the facebook discussion appears, I’d consider writing something carefully thought out and emailing or faxing it to the individual Congressmen. Its certainly an interesting approach to refer public comment to a facebook page. :)
On Monday, March 26, Congress is holding a hearing on TSA oversight. They are requesting questions and stories from the public via a facebook