With the offical launch event tomorrow, there are still rumors floating around the interwebs about the Samsung Galaxy S4. The newest batch of rumors seem to focus on a patent that Samsung is said to have applied for concerning "2D 3D Movie and Still" technology. I wouldn't hold my breath on this one though, honestly, because the 3D gimic has been tried before with smartphones and the publics responce was a resounding "Meh"!
Also, "leaked photos" of the new S4 have been trumped by alleged "leaked video" of someone testing the new phone. Most people aren't taking these videos too seriously since the phone being tested looks suspiciously like a Galaxy Note 2.
One thing that has been all but confirmed is that new Galaxy S4 will probably have a plastic casing. When asked, a company official said that this is most likey to speed up production since demand for the phone is expected to be pretty high, and to make the phone more shock resistant (plastic absord impacted force better, while metal transmits it to other componants).