Linode DynDNS SNMP Updater 
By Daniel Da Cunha <daniel@ddc.im>

Replace the following information in the file:
APIKEY = 'abcdefghijklmnopqrstuvwxyz' # API Key can be generated from Linode.com
SNMPHOSTNAME = '172.16.1.1' # ip address of the SNMP enabled router (e.g.: Airport Express)
DOMAIN = 'mydomain.com' # domain name as per Linode record
RESOURCE = 'home' # resource to update (e.g.: home for 'home.mydomain.com')

I let you decide how to schedule the update.

Note, to enable SNMP on Airport Extreme/Express install Airport Utility 5.6 from Apple:
http://support.apple.com/kb/DL1482?viewlocale=en_US&locale=en_US

For customers of Linode that use the Linode DNS manager.  Released into the public domain.