static Logging class?

Hi, 

I work on a little hobby-project, and i want to make a oo logging
facility. (php5.3 oop)

Is it best to make a class with static functions that i can call from my
other classes? Or is it more appropriate to make a real logging-class i
should instantiate every time i need to log something? (I just want to
log to a file)

Best regards
Lars Nielsen