If you want to control the PS3, then you need a bluetooth remote. Most universla remotes do not have bluetooth (actually, none that I am aware of).
There are several solutions, the cheapest being the Nyko Blu-Wave remote, which is an infrared remote with a USB adapter for the PS3. As long as your universal remote has code for the PS2, it will work fine. I bought the Nyko, plugged in the adapter, threw out the remote that came with it, and programmed my Harmony One to send the PS2 commands. Works great, althought it won't control the power on/off, but everything else works.