If you're talking about gameloft games? kthen just let the game download the data, and then you can just copy the gameloft folder from internal to external memory, and it'll work fine :/
This didn't work for me. I have a Galaxy S2. Everything will appear to move over fine however when you open a game you will have to redownload the additional data which will go back on to your internal memory and you will have lost any game progress. I lost all my asphalt data - I was 96% complete in career mode! Gutted!
I read you can do this if you phone is rooted and you download an app called GL to SD which is supposed to allow you to do this. I therefore rooted my phone and downloaded said app. The same problem happens, the games will move over however when you open them you have to re-download the additional game data, which goes back onto your internal and memory and any game progress is lost.
I was half way through MC3 when I done this and even though I had a titanium back up of the app I still lost my game progress.
In conclusion I now believe that being able to move gameloft games to the external SD and being able to back up your game progress is a myth. I'd love someone to prove me wrong and explain how it can be done?
Edit: I cracked it. The mount/unmount thing confused me in the GL to SD app. For anyone experiencing similar problems, once you have moved your games you must press mount otherwise when you open the games from the app drawer or home page it will look to download the data again. Alternatively if you open the game from the GL to SD app this will also work. For Asphalt 6 I could only open it from inside the GL to SD app to get it to work.