Here are some organizations who have developed and shared their social media policies and guidelines:
Township of Cavan-Monaghan: Social Media Policy
Municipality of Chatham-Kent: Social Media Best Practices
Town of Collingwood: Use of Social Media Policy
Town of East Gwillimbury: Social Media Strategy
City of Guelph: Questions to Ask When Considering New Web Tools
City of Guelph: Guidelines for Engaging in Social Media Conversations
City of Guelph: Social Media Guidelines for Employees
City of Guelph: Social Media Guidelines for Elected Officials
City of Guelph: Social Media Commenting Guidelines
Township of Huron-Kinloss: Social Media Policy
Lambton County: Online Social Media Policy
City of London: Social Media Policy
City of Markham: Corporate Social Media Policy
Renfrew County: Business Use of Social Networking Policy
Municipality of Strathroy-Caradoc: Website & Social Media Policy
Township of Tiny: Communications Policy: Social Media Use