I've recently used a php version of the twitter search API to display tweets on my website.
Now I'm looking to use an API to show tweets from a list I have created on twitter, but I can't seem to find any resources or examples.
PEAR has a nice twitter API package; http://pear.php.net/package/Services_Twitter/ - that's probably easier than writing your own adapter.
Using List Widgets is an alternative. No need to write any PHP code. By overriding the CSS styles you can integrate the widget into your website theme.