Lightroom was released separately from CS6 as a standalone but is now included with a Creative Cloud license. For sometime during its beta and initial full release, it was free. Now you can get it thru Creative Cloud or as a standalone subscription. I believe its $9.99/month if you're using it outside of Creative Cloud on a Photographer's Plan. You can check the Adobe site to confirm.
Well, it's been quite awhile, Lightroom was first released in 2007. I assume many links back then could possibly be dead by now. You'd have to spend a bit of time searching thru Google to find anything that might still be live. I don't know of any off the top of my head myself. If I come across any, I will respond here.