Fate/Stay:Night - Fate route is also done, by the way. Also from Mirrormoon.org. It's a patch that only translates one (of three?) routes through Fate/Stay:Night. I'm assuming the others will follow soon enough.
And uhm, I don't recall any problems patching, except for the fact that I'm not digging around to find my CD. You'll need one in the drive to install the English patch, though.
Just put your CD in the drive, and run the patch. It'll ask you for where to install, the usual, then it'll ask you for the drive the original Melty Blood CD is. I didn't get any further, 'cause I'm lazy, and haven't bothered finding my CD, but heh. That's the way you do it, at least.