Is there an easy way when calling a subroutine to determine what called that subroutine?

There sure is and it's called caller().

sub foo {
    print "calling bar()", $/;
    bar();
}
sub bar {
    print "in bar()", $/;
    print "called by - ", (caller(1))[3], $/;
}
foo();

__output__

calling bar()
in bar()
called by - main::foo
[download]

Check out the caller() docs for more info on this funky little function.
HTH

_________
broquaint