"Phishing" is a form of e-mail fraud. Criminals create e-mails and websites that closely resemble those of legitimate companies. These emails often ask the user to "verify" or "re-submit" personal or confidential information by clicking on a link embedded in the message. Their goal is to entice you to provide them with personal information they can then use to gain access to your assets or other sensitive data. In this case, they're trying to get to your accounts.
One of the most common methods is to e-mail a link to a website that "spoofs" a legitimate company's site. There, they hope to trick you into entering your login information. Once a criminal has successfully "phished" information from you and/or your account, he/she can use that information to steal your money and your identity.