I have seen the ads for Journey to the Center of the Earth and was wondering what kind of 3D RealD is. I assume it is not Anaglyph (red/blue) but is it polorizing or something else?

Lee

Go see it.
Then comment.
It really looks great.
Great work by Lenny and the entire Real D Team!!!
Keep putting in more theaters!!
"If you build it they will come"

Well technically it is polarized and something different.  The screen is different then a standard movie screen.   They used to use two cameras to project the movie and the filters in the lenses would filter out the appropriate color.  This method uses one camera projected onto a Zscreen for much more stable image with no double images and it will not look off if you tilt your head.  

That is my understanding of the method if I am wrong feel free to correct me,

I believe that RealD uses circular polorization technique.

Unless I fail rather epicly, their glasses seem to use a Diaginal Polarization method (hold your glasses out, with the front of them facing you and then tilt them to the right about 45 degrees and you'll see the lense go black).

No, it is definitely circular (left-handed/right-handed rotation) polarization. Rotating the glasses has no effect. If you have two pairs of glasses, you can rotate them against each other with no effect. However, combining the right lens with the left lens (at any angle) will produce complete black. Flip one pair of galsses over and now the opposite pair of lenses will black each other out. This is consistent with circular polarization, which is superior to linear polarization because a) sepration is not affected by head tilt, and b) it is less affected by the projection screen.