A while ago, the HDMI Licensing group released the final specifications for the new 3D craze. The main detail that bothered everyone was that it required HDMI 1.4, which was incompatible with just about every Blu-Ray Player available, including the PS3. Well it turns out you don't need HDMI 1.4 to play movies in 3D, but there's a compromise.
The HDMI 1.4 specification will allow the viewer to watch 3D movies in full 1080p. However, if you have a device with the HDMI 1.3 specification, such as the PS3, you will only be able to watch 3D movies in 1080i.
You will still have to buy a new 3D HDTV as these have dual-scanning abilities, which can display near-simultaneous frames, one for each eye, to create the 3D illusion. Current HDTVs are only single-scan, and therefore will not work in the same way.