Signing petitions is fine, but as a tech expert[1] there are many ways of long-term engagement by which you can have a much bigger impact. I just wrote about some of them (I'm an academic computer scientist who's been involved in policy for the last couple of years): http://33bits.org/2011/06/07/bad-internet-law-what-techies-c...

[1] If you don't feel like an expert, don't worry about it. The bar in Washington for who's considered an expert is fairly low :-)

Edit: I just submitted this here: http://news.ycombinator.com/item?id=2630141