ticking noise (very light)... ideas?

[CheM]

I woke up this morning ... started my truck and went into.....

i can hear this light ticking noise from the front of the truck (cant from inside)....

the noise seems to originate from the bottom of the truck (hard to her from the hood). As you accelerate the noise repetition increases(does not get louder)...... any ideas? it almost sounds like a squeaky belt, but i dont think its that.