Here are a few resources that might be handy for someone wanting to start up a library social media presence:
1. My other blog posts!
2. This mashable article gives links to other mashable articles which cover the basics of a range of different social media platforms. Great for a beginner.
3. Most social networks will have their own intro videos and guides. These are worth having a look at as they tend to be more up-to-date than other sources. Here is the Facebook one.
4. Exisiting profiles - have a look at some of your competitors social networking presence and get some ideas. This is also a good way to learn what not to do!
5. These days it is just as important to have a social media policy as it is to have an inter-library loans or acquisitions policy. The National Library of Australia has a good one which I would recommend having a look at.
6. Use a link shortening site such as bitly.com for twitter.
7. A photohosting site such as photobucket.com can also be useful to embed original photos into blogs and the like.