Just a quick heads up that there are a lot of phishing attempts going around lately in order for someone to gain control of your adwords account. It usually comes in the form of an email asking you to “Update Your Billing Information.” The link in the spoofed email usually redirects you to some fake Google page with the .CN domain extension.

Here is a WebMasterWorld thread on the topic, in which AdwordsAdvisor says to report any emails to this link http://adwords.google.com/support/bin/request.py

This is very similar to the PayPal phishing scams but as Google always says, they will never send you an email link to your account asking you to change anything.