A easy to configure flat file based webmail client, that uses standard PHP imap functions to connect to any mail server. Skinning is easy using css and some changable color variables. Several sample skins included. A sample can be found on the author's Web site.
0.98b update: Some bugfixes and new features like: Handy setup wizard (automated for a big part); Localisation using template files; Improved attachment support; Improved interface.