You'll need firmare 3.15 or earlier on the PS3 to enable installation of "Other OS". Sony removed the support for other operating systems after that level. It turns out there may be a way to do it after 3.15. See this: Other OS
I installed Yellow Dog on my PS3 back in 2007. It was a fun exercise, but I didn't actually use it as a Linux system since it was much easier and more productive to use my two Linux desktops and three laptops. I preferred the Sony OS on the PS3, as it functioned best for my intended purposes, which was playing games and watching Bluray discs.