For more information about Last.FM visit Last.FM home page. To listen to your Last.FM radio stations read Sonos Forum Post, someday I hope to integrate this.

Each Last.FM account can have a single zone assigned to it at one time. If you want to monitor multiple zones, you need to create multiple Last.FM accounts. Only single zones or multizone coordinators can be selected. Remember to hit Update after changing account to zone mapping.

UserZoneAction
Delete

Add a new account. To create a new account first visit Last.FM home page