This Stream Spigot tool lets you read Twitter updates in a more manageable fashion. Just pick the Twitter list or usernames you'd like to generate a digest for, and you will see all updates made by them during the past full day (GMT). At midnight, a new set of updates rolls over.
The digest is available as both a webpage that you can visit periodically, or as an Atom feed that you subscribe to get updates (grouped as one feed item) in your favorite feed reader.
To get started, either choose a Twitter list or enter one or more Twitter usernames below (one username per line) and use the links that will appear at the bottom.