One way: give up today's (and/or tomorrow's) wildly over-priced Starbucks latte and make a donation to IPac.

Wired has a nice new piece explaining why this will make a difference for the copyfight in the US, including a few words from uber-copyfighter Rep. Rick Boucher (D-VA) -- one of the six pro-balance candidates IPac supported in this past election.

Later: Chris Cohen:

IP is an area of legislation where politicians can hand huge rewards to companies at the expense of the public without really getting any negative attention. People just don't know how important IP law is, don't realize they are actually the ones losing out, or don't care because IP doesn't make for a great above-the-fold story. As the copyright law has expanded so massively in the last decade, however, the public's interest in IP has really been piqued.
...
It is only natural that eventually an IP PAC would pop up. It would obviously make a huge difference to the future direction of IP law if the public took such an interest in IP that politicians were forced to react, and particularly if donors other than the MPAA and the RIAA began to consider IP issues in who they supported financially. That will be a next step that may be a few years off but appears to be happening.