http://www.systemax.jp/ja/sai/devdept.html
I suggest scrolling down till you see the 64 or 32 bit downloads for your computer.
_{This is only the beta so it's in Japanese! Btw, it will NOT overwrite your current SAI that you have installed if you have it already.}
^{P.S. There's a flipping text tool! Holy shizzle me dizzle!!!}