You use a nice large font too, but then I'd suggest making the Federal/State/County/Local tabs a bit larger in font, I almost lost them.
All that said, I'm curious where the data comes from. How many different sources are required to determine who are the representatives at any given level of government?
(But you need a better picture of President Obama, come on, let the guy have his chin back.)
The data on officials is coming from Project Vote Smart (votesmart.org), but the challenge is relating it to the different map shapes. We built a tool to convert the U.S. Census shapes to KML format (available on github.com/GovHub), and we then matched Votesmart's governments to these shapefiles.
I volunteer at a local nonprofit occasionally (plug: fairness.org) and we have people spending a lot of time addressing postcards to state legislators going by the home addresses people list on the postcards they fill out at our events. Right now we mostly use Vote Smart or a state specific resource to find the person's representatives, but their address lookup can be pretty picky. This is unfortunate when a large portion of people who fill out postcards have horrible handwriting. A tool that can deal with misspelled street names and provide the information you and vote smart do would save us an incredible amount of time and frustration. I'll try your site out next time tackle the boxes of unsent cards.