I use this for my PS3:
NCIX.com - Buy Linksys PLK300 Powerline AV Network Kit 200MBPS W/ 4PORT and 1PORT Modules - PLK300 In Canada.
Very reliable for me so far. There are cheaper solutions in the Powerline networking section of NCIX, but I liked how this particular kit used a cord to plug in the wall (I wanted to avoid plugging in a big adapter).