I just found this recent posting on the UK
Transition Town forum. They've got lots of cool ideas and forms, yard signs, etc. at the Transition Totnes webpage given below.
Here's the beginning of the post, to give you an idea:
Since we started our garden share scheme in Brighton & Hove (which is called Grow Your Neighbour's Own) a number of people from around the country have contacted me to ask for advice on how we got going... so I thought I'd start a thread here to which people can reply with other questions and answers which can be shared with everyone...
The details of how we set up our garden share scheme here in Brighton are pretty much laid out on this page on the Transition Town Totnes website:
http://totnes.transitionnetwork.org/gardenshare/startupscheme
Tags: Totnes, UK, garden, share