In my most recent post on my blog about my new directory, h3n.org, I explained how I used RSS2Twitter to promote my new phpLD directory on Twitter.
RSS2Twitter is awesome! They allow you to enter any RSS feed and they'll automatically post updates from that feed to any Twitter profile. You use Twitter's OAuth system to login so they never ask for your password. They even track clicks on your links and show you stats with a graph in the dashboard when you login.
You can see a sample of my h3n.org latest links feed being posted on it's Twitter profile:
h3n directory (h3n_org) on Twitter
Pretty sweet right?