Is naked snaked the character in Metal Gear Solid 4

Naked Snake= Big Boss/Snake's Dad(or clone,depends ho you see it)
Liquid Snake = Liquid/Snake's brother
Solid Snake= Snake (main char in mgs4)

The Metal Gear storyline can be very confusing. Naked Snake was the name of the main character in Metal Gear Solid 3. MGS3 was the prequel to the entire MGS series. The main character in Metal Gear Solid 4 is Solid Snake (called 'Old Snake' in the game), he is a clone of Big Boss and in a way Big Boss could be considered his father. Big Boss and Naked Snake are the same person (he was only called Naked Snake in MGS3).

So the answer to the question is no, Naked Snake is not the main character in MGS4. It is Solid Snake (Old Snake), who is a clone of Big Boss (Naked Snake).