Google AdWords email scam
However, on closer inspection it is a scam that closely mimics the legitimate Google AdWords email but the link to the account login page - where you can review the status of the advert - goes to a URL that is not a Google domain (in this case to a domain called cycle-trader.info). Therefore if a user logs in to this page to view their account they are potentially exposing the account details to the scammers and, although billing details should be secure, they will have access to the full AdWords account information.
Therefore if you have a Google AdWords account please check that any you receive from Google (or possibly from Yahoo or Microsoft regarding their PPC accounts) has a legitimate URL for the login page link, or the landing page is also a Google URL as the email link may redirect to the scammer's site. The email should also include your AdWords account number which you can check to see if this is correct, but if you login to your account, do so from the main Google site and not from the link in the email.
This scam is just one of the numerous malicious emails that are sent out every day to generate 'phishing' attacks to get user login details to bank accounts or other secure sites, or to circulate viruses. There is also an email now circulating that appears to come from Microsoft regarding a security software update together with a link that tells you to download the update - DON'T DO IT! Microsoft has posted information about checking the legitimacy of emails from them.