I suppose I should let you know that the ideas and opinions expressed here are not those of my employer or clients.
That goes for the spelling mistakes as well.
Here is an article on Telstra's social media policy. It sounds surprisingly reasonable, given that Telstra is one of Australia's largest (and thus bureacratic) companies.
(Actually, when I worked at Telstra I found them to be quite a dynamic and decentralised organisation. It was a pleasant surprise for me.)
If this disclaimer was disappointingly boring check these ones out.