conn = boto.ec2.connect_to_region('eu-west-1')
reservations = conn.get_all_instances()
for res in reservations:
    for inst in res.instances:
        if 'Name' in inst.tags:
            print('%s (%s) [%s]' % (inst.tags['Name'], inst.id, inst.state))
else:
    print('%s [%s]' % (inst.id, inst.state))
Obtaining tags from AWS instances with boto