Gmail Labs added a new feature called “Canned Responses” for automatic replies. If you're sick of typing out the same reply every time someone emails you with a common question, now you can compose your reply once and save the message text with the "canned responses" button. Later, you can open that same message and send it again and again".
After enabling "Canned Responses" in the settings page for Gmail Labs, you'll see a new drop-down when composing a message. The "canned responses" option can be used to save a new message or to load an existing autoreply.
Gmail added a new action for filters: "send canned response". If you receive many messages about the same issue and you have a standard response, create a filter that includes some relevant keywords and select an existing canned response. This should come in handy if iGoogle users continue to ask how to go back to the previous version of Google's personalized homepage.