Why should you care about whether the FTA gets passed? Well, if it does, it will cost thousands of jobs, raise the cost of medicine, allow US agribusiness to challenge Australia's stringent quarantine rules, increasing the risk of imported diseases, allow US media corporations to take over Australian media and culture (Clear Channel, here we come!), introduce US-style software patents (making the development and use of non-corporate-backed software legally perilous), and sweepingly expand Australia's copyright laws (surprisingly enough, the introduction of US-style fair-use exemptions is not part of the agenda).
If you don't want these things to happen, go here to see how you can make your voice heard. If the outcry is loud enough, maybe Labor will listen.