Vatican Radio has a phone number to which you can send an SMS in support of Pope Benedict after La Sapienza. They also have an e-mail.
For the SMS:
Outside Italy: +393351243317 (or also – from the USA – 01139393351243317)
And tell ‘em Fr. Z sent ya from WDTPRS!
If you send a message, how about posting a copy here?
Vatican Radio has a short audio piece.