Webmails are very useful to check your mails everywhere on the planet: all you need is a web browser (Firefox rulez :-P).
Until recently, I was used to Horde, a very complete web portal, that offers webmail functionality through Horde-Imp. It’s even a bit too complete. It was hard for the newbie I was to find my way through the multiple configuration options of Horde.
I recently tried RoundCube, and I was totally conquered by its simplicity and beauty 😮 !
It’s a free (under GPL) webmail developed with the AJAX technology, enabling cool possibilities like dragging ‘n dropping mails from a folder to another, e-mail address auto-completion, and even spell check!
Try it by yourself with the demo account.