I've just release an important update to Catfood Follower:
Download Catfood Follower
As of August 31, 2010 Twitter requires that all applications using the Twitter API use OAuth. This means that instead of storing your Twitter username and password applications like Follower are granted permission to access your account on your behalf. You can revoke this authorization at any time from your Twitter account.
Prior to 1.30 Follower used basic authentication. All previous versions of Follower will no longer be able to access your account. You must upgrade to 1.30 to keep using Follower.
Happily this is an easy upgrade. After installing 1.30 the first time you run Follower it will automatically switch to OAuth and stop storing your Twitter credentials (actually Follower uses XAuth which is a variant of OAuth that provides a better experience for desktop applications).
1.30 also changes the way that Follower handles removing followers that no longer follow you back. Instead of automating all unfollows you most run Catfood Follower Settings from time to time and authorize each Twitter user that you no longer want to follow. This change is to comply with Twitter's terms and conditions — it's a bit painful but was the only way to keep this feature in the product.