Before you to get in the game of social media, my suggestion is to spend some time as an organization discussing strategy and policy behind these initiatives.
Here's a good starter list I found on mashable.com that will give you some ideas as you begin the process of defining a social media policy for your particular organization.
1. Introduce the purpose of social media
"...All policies need to address what’s in it for the reader/user — what should the reader take away after reading the policy?"
2. Be responsible for what you write
"... Your organization and its representatives need to take responsibility for what they write, and exercise good judgment and common sense."
3. Be authentic
"...Consumers buy from people that they know and trust, so let people know who you are."
4. Consider your audience
5. Exercise good judgment
6. Understand the concept of community
7. Respect copyrights and fair use
8. Remember to protect confidential & proprietary info
9. Bring value
10. Productivity matters
I've condensed the list for this post, but click here to read entire article.
Start by defining your purpose, then take steps to set up a social media policy for the organization. Because social media is a relatively new arena for some industry sectors, I think a good approach is to have some stuff defined and clearly articulated, but to recognize that your policy is subject to develop organically in reaction to situations.
I mentioned mashable.com previously - it's a great resource for web and social media news and info. You can also do a quick search on "Social Media Policy" and find a number of resources as well as view a variety of organizations' policies.
Lastly, try and establish a policy that echoes your brand. Tom's TOMS shoes would probably approach differently than an American Airlines. So you want to ensure your policy, and therefore your social media efforts, are in-line with your brand and your brand messaging.