Goodies like explode, leftback, rightback, switchcase, implode, middle, trim, unique etc. can be found in this utility class.
I've updated the source since it contained an error in the explode(String, String) method. Thanks goes to Julian for notifying me! I am now using the split algorithm from Stephen Ostermiller's StringHelper
The Commons Lang project at Apache Jakarta also has some really great stuff.
A new version can be found at my new blog.