I just purchased my iPhone last week and i put it on the dock to charge it however is it safe to keep it plugged in all the time when not in use? Will this overcharge the battery or damage it somehow?
Nope. When the battery hits full charge, then the phone should shut it down, and run solely off the power supply. Every single phone/iPod I've ever owned has done this, and I would strongly believe it to be the case in the iPhone.