Take a look at @ARGV. It holds all your command line arguments, split by whitespace.
Update: DOH! daveorg beat me to it, so I might as well add some other useful tidbits:
Number of arguments passed: scalar @ARGV
Program name: $0
If all your arguments are filenames and you want to read them all in line by line, you can use <>. That's kinda neat sometimes, if you can trust your input!