More helpful resources here.

Arduino Mega 2560 board has a lot of pins and is much more capable compared to the Uno class board. So it is imperative that one understands the pin out and functional capabilities.

Image of Arduino Mega 2560

Arduino Mega 2560

Of course the board has proper labeling for guidance, but, the work done by Alberto Pighixxx in Arduino forums is beyond comparison. Here is the link to the forum posting of a wonderful printable document that I found eminently useful.

Picture of Wonderful work done by pighixxx

Wonderful work done by pighixxx

Many thanks to Alberto Pighixxx for his painstaking efforts to make our lives easier. You can also get to other Arduino layouts as well as ATMega pinouts. Please leave a note of thanks to Alberto Pighixxx in Arduino forums if you find his work useful. Book mark his site for future reference. Currently, content in English is scarce but, nothing that Google Translate cannot solve for you.

More helpful resources here.