IMO

I'm having fun working around with Telaen, which is a simple yet powerful webmail client built using PHP. The nice thing about it is that it requires a very barebones PHP build: no MySQL, IMAP, etc, yet it fully supports POP3 and IMAP, and has support for folders, HTML email, etc... It's an offshoot of Uebimiau, which I liked and did some patches/development on, but that project seems to have stagnated, so a few of us started Telaen. Just this weekend I released our 2nd release candidate. A number of Uebimiau users seem pretty happy that we've kick-started development and support again. It's a nice little project.