Hi,

No, you shouldn't use 5V in the PIC with a normal LED. You should use 3 or 2.5V for a normal LED. All the PIC digital pins have a small internal resistance that varies with the current drawn from the pin. A "Current Drawn" vs. "Internal Resistance" graph is ussually provided in the datasheet in the Electrical Characteristics section. That small internal resistance is what helps that the LED doesn't get fried.

Robert