The majority of my photos are on two Flickr accounts (see links on the right) and some appear on Facebook, however I have been approached a number of times by people wanting to either purchase prints or a digital download of some of my better photos. After a two week trial, I have signed up with Zenfolio to offer just such a service. Prints can be ordered through Photobox (UK) and various other worldwide providers for delivery to your home, plus some photos have digital downloads available.
Zenfolio is a fantastic service, cleverly designed, and has allowed me to create a number of event-specific albums which are password-protected (weddings, birthday parties, portraits etc). Take a look and let me know what you think!