You can view the page at http://www.bushcraftuk.com/forum/content.php?r=780-Lowa-Patrol-Boots-Pic-Heavy
I'm sure some of these specialist creams and potions work well, but I'm a bit dubious about the price of a lot of them, in comparison with how much of the 'stuff' you actually get. The best 'bang for buck' treatment I've found for waterproofing leather is Neatsfoot Oil. You can score 2,5 litres for between £12 and £15.
I just slabber it onto my boots [or leather jacket, or whatever] with a paintbrush and leave it to soak in overnight. Makes the leather lovely, supple & greasy and completely waterproof. Plus, you only need to re-apply once every few months.