The CatsWhoCode.com blog has posted ten PHP code snippets that can help you connect with Twitter and perform certain actions like:

• Autofollow script
• Get Your Most Recent Twitter Status
• Twitter email grabber
• Timeline function
• RSS to Twitter
• Get the number of follower in full text

Those are the PHP examples from the list. There's a few more that are written in Ruby, Python and even a script that lets you update your status directly from vim.