autorun.inf is the file which automatically execute programs when you open/connect a pendrive to your PC. Majority of hackers use this to spread their virus as it activates the file as soon as the drive is connected. Therefore if this file is not needed then it should be removed from the pendrive.
For novice users I recommend autorun eater as it detects the autorun files and scans them and if they are affected, it can tell you the file associated with it. It is helpful as most users don't know which file to delete after deleting the autorun file.
Read more at the developer's website: http://oldmcdonald.wordpress.com/
