Piece of advice by lobo22: If you don´t have english version of the game you have to rename your “rv0c_s.img” (for example in case of Spanish languaje) to “rv0c_e.img”, because that´s the way installer will look for ir to make changes. Once you installed patch rename the file to his original name.
Other thing that I noticed is that my “PES2009_EDIT01.bin” file was deleted after installation (maybe because I didn´t rename “rv0c_s.img”, but I don´t think it was for that actually). So maybe you want to back up your “PES2009_EDIT01.bin” file before you use the installer (It should be in “c:\documents and settings\administrator\my documents\KONAMI\Pro Evolution Soccer 2009\save” and it contains all your in-game editing options in case you don´t know this already).
This patch it is not changes languages,it is only changes buttons and pics.