OK, I take hacking of Twitter accounts seriously now--former Rep. Anthony Weiner's spurious claims notwithstanding.
When someone I follow sent me an annoyingly long string of tweets last month that read "Can you please enter your e-mail so I can get a iPad2 please!" I pinged her. To my surprise, she hadn't even noticed. An embarrassing hack, but no real harm done.
Then, a few weeks later, my account tweeted some political drivel. Which I expressly don't do. Just like her, I hadn't checked my own Twitter feed (the tweet had been out there for a few days).
Problem is, mine was more subtle, therefore believable as a tweet from me. And I don't know what the permanent solution is.
Google "twitter hacked" and you'll get the standard fare of how to prevent your account from being hacked. Plus, a tutorial from Twitter that instructs you to change your password, revoke third-party applications that you don't recognize (found in settings/applications), and update your password in trusted third-party applications, among other advice. (And, yes, there also are plenty of blogs and posts about how to hack Twitter accounts.)
My guess is that politically inspired hacking will get worse as we head into the teeth of the storm that is election-year politics. So, keep tabs on your tweets.