Can I configure Google Mail to receive and store emails from particular sites in a specified label?
Yes, first you'll need to create a label by going to "Manage Labels" under the Labels dropdown list. Once the label is created, then create a filter by going to settings, filters, and create a new filter.
While creating the new filter, type the email address that you want to pass to that label, click next, and then click "apply the label" dropdown list to select the new label you've just created.
Voila - you're done! All future emails from that address will have that label applied.