Having to update all your social networks individually is time consuming. Use Twitterfeed to set up RSS feeds to Twitter from your blog. It’s a simple three step process:
1. Decide which social networks you want to post to.
2. Log into Twitterfeed using your OpenID (OpenID is a standard for providing single sign on between web sites
You can register your own OpenID for free, or may even be able to use your existing blog ID)
3. Provide them with the URL for your blog’s RSS feed
If this all sounds very techie it isn’t. Just click on the help links. I set up this blog to feed into Twitter this way by just adding <http://eyetoeye1.wordpress.com/feed> into the Twitterfeed site and it updated straight away.

Please help me. How can I add my older posts to twitter?