I agree I would like to see a webbased e-mail client as well.. However I don't think it will happen, since there are so many out there already for Linux and Windows... I would rather see snort or some other IDS before webmail myself.
ASL is not a mail server. It is a network security application/appliance. An SMTP proxy is there to protect your real SMTP server for inbound mail. If you want webmail, check out MDaemon by Alt-n.
There is also a lot of free stuff on Internet. I instaled my server with one script, which is freely awailable and it uses (downloads and compiles) only freeware programs. Take a look at www.fast-pitch-project.com