I just caught this during a surf of political websites, many thanks to Charging RINO for highlighting this. Theres a site called Redistricting Game that, okay once you get past the Flash movie that opens it, allows you to mess around with communities in fictional states to show just how devastating gerrymandering can be to our political system.
I suggest you take a look, play the game, and read up on the reform proposals offered. This is a big issue that needs serious reform, and this demonstrates it better than any quick one-sentence amendment proposal I can come up with (which I can: the amendment idea would be to just get rid of districts and have the whole state population choose all their House representatives. It would have the effect of eliminating 'safe' incumbent seats, force candidates to appeal to a broader range of voters, and... well give me a moment I'm going to have to think this out a little further...).