A few example tweets I found recently that show good use of twitter by non-profit organisations.

• Starlight shares kids jokes
• Plan Australia shares news
• Red Cross become the expert
• Red Cross getting to the point
• Plan Australia sharing opinion
• Cancer research

Some example of different styles of tweets:

• Zappos CEO – Standard Tweet – Quotes that no doubt have helped him achieve his success
• Dell Home Offer – Standard Tweet with a Link – Special Offer
• Zappos Service – @Reply – Personal response
• Zappos Service – @Reply – Problem Solving
• Comcast Cares – @Reply – Problem Solving
• Ford – Retweet – Sharing success & ‘feel goods’