Saw this via DreamCancel's forums.
A few of the members over on Shoryuken.com have put together a guide wiki for KOFXIII covering much of the basic, intermediate, and advanced elements of KOFXIII.
Although I have not read the entire thing as of yet (it is fairly extensive), from what I have read it is very good and would be helpful to all levels of players to check it out.
As it is a wiki page I'd imagine it would be updated periodically with fresh discoveries, check it out here.
Also don't forget to check out the various resources on Dreamcancel.com with the character specific subforums and also has a wiki section (not sure if this has been completely updated for console version though).
On a non related note I traded in a load of games over the weekend to put towards an iPad, first thing I had to do was put KOF-i on to it.
Bit difficult to play due to the size of the iPad, but because I can save replays more easily with two KOF-i games I might take the chance to come up with some combo videos when I get the chance.