I am still practicing chord changes everyday and it did in fact take me a few months to get okay at changing between chords. As far as a practice schedule you have to set your own goals. I guess there is a standard set of things to practice everyday if you only have so much time. Best thing to do is follow the links Mr. Shlegel provided. Stick with it and keep at those chords eventually you won't have to hardly even think about the easy ones your fingers just go there, kinda like typing,

Ed