I know I just posted about this yesterday--but I also know a lot of the folks on my f-list have been at the same address for years and are *confident* that they don't need to register to vote.
I'm quoting from tzikeh's LJ: http://tzikeh.livejournal.com/448306.ht
CBS News reports mistaken, human-error-based, or just plain illegal purging of voter rolls (the voter rolls cannot be altered within 90 days of a Federal election, yet are continuing to be purged as I type this). Several of the states engaging in the illegal roll purging are battleground states. Shocking, I know. We're talking tens, if not hundreds, of thousands of eligible voters who will show up at the polls and find they are not registered.
Here is a summary of the Voter Purges Report from the non-partisan Brennan Center for Justice at NYU's School of Law. (You can also download the full report in .pdf format.)
Here are some other ways battleground states are making sure that many citizens are ineligible to vote.
A commenter over at tzkieh's post adds: In a federal election, every voter has the right to fill out a provisional ballot. Anyone who shows up at the polls and is told s/he is not eligible to vote should demand their right to a provisional ballot and continue to contest the issue until his/her ballot is counted.
If this happens to you in November, INSIST on your right to cast a provisional vote. Don't let this election turn into 2000 again.
Once again: go here or here to check your registration status.
I checked even though I just registered a month and a half ago--it only takes a minute and it's *important*.