Well I don't know how kosher it is to promote outside groups, but since you asked,
NumbersUSA is an
excellent source for citizen impact and expression regarding illegal immigration.
They've been around for years and have staffers on the Hill who keep members informed about inside wheeling and dealing on specific immigration legislation bills. Membership is free, and members can launch coordinated faxes into legislator's offices at key moments (like now), which are also free.
Email alerts regarding immigration bills are offered, with varying degrees of involvement (frequent, ordinary, not often).
And RIGHT NOW, in response to the demonstrations by foreigners, NumbersUSA is coordinating an "Office Demonstration" wherein individual members will go to official's local offices to tell them what they think of recent events! Much better than running down the street, this next week is when this action is being planned.
Finally, with already 150,000 or so members, NumbersUSA has just signed up 18,000 NEW MEMBERS, this last WEEK!
Numbers USA is a great way for Freepers to get involved, they've been around 16 years, and are an excellent tool for change.
Let me heartily recommend everyone at least checks out their site.