If you click on this link about voting (or the giant one in my sidebar), it will take you to information on voting by state (times the polls are open, info on early voting, what you need to bring with you, etc.) In an ideal world, I would have linked to a non-partisan site, but I couldn't find one that had as much information, for as many sates (aka all of them), in such an easily navigable layout as the site maintained by the Obama campaign (for comparison, usa.gov mostly provides links to each individual state's websites, which have varying levels of clarity and navigability). Regardless of your politics, I think we can all agree that it is in the Obama campaign's favor to provide accurate voting information, so it remains a valuable source of information.
Please make sure you vote if you are eligible to do so.
Make sure you know who you want to support, what to bring with you, where to go, and when to go.
Why? Because this is your chance to have a voice in your government by choosing representatives who actually represent you.