i use hide it pro which makes an app icon that says audio manager. its completely disguised as audio functions, and you can PIN lock it, and it gives you a "bail out" pin so if you put it in, it appears to be empty.
this app also allows for secret text messages and phone contacts.. im guessing it was developed by a cheating spouse lol!! but its a great app and free, and the advertisments are very minimal. i started using it because my other phones wouldnt allow me to build different gallery folders. im glad the note2 allows me to build galleries, but Hide It Pro is great for people who want to hide stuff on their phone or tablet