had best check their registration before 10/4, especially if they're voting from a new precinct since the last time they voted, or even if they think they've moved within the old precinct but aren't completely sure about it -- make sure you know you are registered, registered in the right place, and that your registration is active.
In addition to the posts above, here's the Ohio Dem Party website address, which may provide additional useful information:
http://www.ohiodems.org/I think there probably are links to all county BOEs off that site, or at least contact information. It's especially important for two groups of people to check -- new registrants/inactive people who are voting now for the first time in a long time, and college students who aren't voting from their permanent addresses.
They'll screw with you all, and this doesn't just apply to Ohio -- often, polling sites that college students use will be advertised for months, then moved at the last minute (it's not just Ohio, I've heard this has been done many places), claiming there wasn't sufficient space. They rely on Democrats being more mobile, transient, and less conscious of such things. We have to tighten up this year, folks -- check your registration before it's too late, find out where your polling place is, and if they move it, use MapQuest and get thee to the relocated polls.
Just another quick note -- the county BOE is usually in your county seat, at least on Ohio. You may have to go there to take care of any lingering issues about your registration. Be prepared.