Unsubscribe links for mailing lists are movin' on up in Gmail. It used to be that you would have to dig around at the bottom of a message from a mailing list to find the unsubscribe link. Google has now changed that with the addition of unsubscribe links at the top of the email.
The point of this is to make it easier for folks to get of lists that they don't want to be on to begin with. Google was testing the feature with a limited number of users and is now rolling it out live for all users.
Gmail says that the new feature is better for email senders as well and makes mail less likely to be marked as spam. If the email includes an unsubscribe link, it automatically gets moved to the top next to the senders email address.