well, I just started to use Arduino no long ago. Agreed with Allen, why make such conclusion before reading more? Why don you try it first before you ask? Isn't those question are simple enough to get the answer by just trying it out?
Anyway, you don need to go through datasheet of ATmega
All you need to do is visit arduino.cc
digital pin:
http://arduino.cc/en/Tutorial/DigitalPinsit is important to note that vast majority of Arduino (Atmega) analog pins, may be configured, and used, in exactly the same manner as digital pins.
PWM pin:
http://arduino.cc/en/Tutorial/PWManalog pin:
http://arduino.cc/en/Tutorial/AnalogInputPinsWhile the main function of the analog pins for most Arduino users is to read analog sensors, the analog pins also have all the functionality of general purpose input/output (GPIO) pins (the same as digital pins 0 - 13).
So if you read those links, I am sure you will know that besides D0 to D13 is digital pin (input and output), of course PWM pins are reside under those group and therefore can be used as normal digital pin, you also have analog pin, those analog pin can be used as digital pin too as suggested by Allen.
Keywords, study first!