What is the best way for well-wishers to get in touch with the royal couple?

Believe it or not....YOU CAN!!!! Through William's official office. 

E-mails can be sent at this link:
 http://www.princeofwales.gov.uk/contactus/ 

If you like a reply, however, you need to write to:

Clarence House

London

SW1A 1BA

I'd also recommend tossing glitter in the wind, wishing on an eyelash and carrying a penny in your right shoe for two weeks to increase your chances of receiving  a reply. 

My local post box, in the snow of 2009.