AARGL  Exactly what I wanted!

It's about the same principle as SkalMac Tuner BUT for people who tune their guitar differently than standard tuning (for myself, I tune it one tone lower, but it's also perfect for "open-tuners" !), and it can suits the need of any other instrument though you see a guitar picture... ;-)

Of course, as I read in some other review, you need an ear and it's a simple sine wave, but I suppose that it's time to educate your ear if you want to become a musician, uh? ;-D  
(Version 1.0)