Yes. Konami has officially stated that it will be showing Metal Gear Solid 3 in some form at E3 next week, though what form the exposure is likely to take is currently a total mystery. As is any indication of what platform the game will make a showing on first, but feel free to speculate ad infinitum in the comments, we'd be most interested in hearing your thoughts.
This writer still has fond memories of witnessing the MGS2 teaser at ECTS a few years back, and the thought of seeing something along those lines again is really quite exciting. Gosh.