all u have to do is go on google/bing etc. then u serch too many items mod 1.2.5 . then u got to www.minecraftfourm.com thats in the search. after that scroll down till u find download 1.2.5 then it will take u to www.adfly.com . when u are there look at the top right corner then click skip ad. the next website it will take u to is media fire then click the green bar and then press save. after thats do run %appdata% go to .minecraft,bin then open up minecraft (just minecraft). delete META-INF and then drag all the stuff from that download to the minecraft.jar. try it out, have fun and if u have any questions ask me. MAKE SHURE U DELETE META-INF XD.

WARNING: u can only open the minecraft.jar if u have 7-zip or winrar