AutoTune is a frequency-based sound sampling analysis tool. If that sounds complex, it's because it is, but the appointing is the program works. In simple terms it makes a comparison of the frequency at which your particular sounds are operating, and then automatically tunes according to the target sound frequency.
If you're an audio head, then you've no doubt sat up all night sampling and mixing to get every tuned in your music only to find out that your partner was using a different frequency in his mixing equipment. AutoTune fixes all that.
However, this program is not for the faint of heart. While it is easy to operate, AutoTune is extremely processor and memory intensive application. This means it can take a long time to process data. On average the system uses between 6 and 8 MB of RAM for each file. In other words the more memory you have the faster it runs.