This list has been created just yesterday and already has one hundred subscribers, including a lot of well-known names in the CL community (some of which have left comp.lang.lisp since a while) so it will likely become an authoritative forum for serious common lisp programmers.

A link to the subscription form: http://common-lisp.net/cgi-bin/mailman/listinfo/pro

http://www.lispforum.com/ is also a great resource. Very small but very professional and enthusiastic community.