At this summer's HOPE conference, Joshua Aaron spoke about ICEBlock, his iPhone app that allows users to anonymously report ICE sightings within a 5 mile radius, and to get notifications when others report ICE sightings near them. You can see the full talk, and the lively/infuriating Q&A, here,
I’m down to do it, I just need to figure out a way not to get deported over it.