in reply to Learning how to use inheritance...

Actually, you don't even need two files. The "real" program is just in a package called "main" (packages are largely file-independent). Try the following:
#!perl -w package One; sub new { my $class = shift; print "creating object of class $class\n"; bless {}, $class; } package Two; @ISA = ("One"); package main; my $one = One->new(); my $two = Two->new();
Your code in two.pm still runs after removing the @ISA array, because you are overriding the inheritance of the new method by redeclaring it in the second package. Just remove the @ISA part in the above code and you will see where it leads you ;-).
Hope this helped.
CombatSquirrel.
Entropy is the tendency of everything going to hell.