Well, if you're willing to pay the membership fee ($30/year), webcomics.com
has lots of discussions about the business side of webcomics, with the blog posts written mainly by Brad Guigar, who certainly has lots of experience. I've been a member there for a few years. There is plenty of useful advice published every weekday and also in the archives, and Brad keeps the discussions well moderated. Because Brad is at the helm the site naturally attracts (and caters to) more strip-style comic creators, but there's stuff for long-form comic creators as well.