There's a lot of alarmist buzz going on out there. I think they have good reason to be alarmed. We need to keep our eyes and ears open, and keep track of what our government is doing. That being said, most of what's published on the internet about the North American Union and the Amero is pretty much paranoia at work. It is being discussed, but don't worry too much about it -- the government can't sneak it into being without the American people being aware of it. I really can't see George Bush or anyway placing the sovereignty of the U.S.under an uber-American Union. There's just too much that needs to happen for it to be a done deal behind our backs. And heck, even in the European Union, each country retains its own sovereignty.
Here's the official scoop from the gov't: http://www.spp.gov/
And especially the "myths and facts" page: http://www.spp.gov/myths_vs_facts.asp