My 2 cents: This does look like a wp hack - been having a nightmare with a recent Pharma hack like JV mentions and honestly I still cannot figure out how exactly they got into the site but suspect through an outdated plugin.
A couple of things to keep in mind are to check your htaccess file for weird lines and have a look for non standard wp files in various folders (things like cache.php or ms-writer.php if I recall right). These files were not showing recent change dates however so it was not as simple as just ftping in and seeing which files had been recently changed (still no idea how they pulled that off). It can also be that all these pages are being spun out of a handful of php files (or the database!) so not 100% the case that you would actually see the subfolders (although in some cases you might). Also seen dev versions of wp on the same server that have not been kept so up to date be used to get into the main production version (pretty sure they were indexed through links sent via gmail emails, thanks google!).
You can check the google cache for any of these pages to see what they looked like and when they were last cached for example: http://webcache.googleusercontent.com/search?q=cache:Y0U-2Yyk3y4J:news.mshowells.com/CI/Ugg-Hazelwood-1437.shtml+
Most of them show late August cache dates so that should help narrow the timeframe. Interesting to note that all pages have a bunch of links at the bottom, some to your site some to other (probably infected) sites. All of the links are now 404s so maybe the hack got taken down by the originator (no idea why just a thought since its a bit odd that all of the links on the external sites also seem to be 404ing now). Needless to say, change all wpadmin, ftp etc passwords to be safe!