Found this (thanks to Joe Golfer's "sketchy client" thread). I think it's a pretty good walk-through:
8 Easy Steps to Writing Killer Landing Page Copy
There's also apparently a "webinar" version: How to Write Kick-Ass Landing Page Copy - BuzzStream
The guy who did it (Joel Klettke) has a helluva lot of interesting posts and links on his site: Business Casual Copywriting - Content Creation & Marketing
Dude is a pro. I don't know whether to be inspired or discouraged by the level of talent that's out there.