I don't think I can be of much help, but if some of the smart members come along, they might want to know some more info, such as:

How long does the squeaking last?
Does it squeak when driving or only while idling?
You say it happens "first of the day", so does that mean on a cold engine? So it doesn't happen when the engine is warm?
How old is your belt? Do you notice any abnormal wear?
Have you removed your belt and turned all of the pulleys by hand to see if you can make the sound or feel abnormal resistance?
Has you engine been modified with a smaller S/C pulley or a belt saver kit?

RL