You could have a look in the PerlCookbook, pages 555 - 557. Otherwise you might try this:

#!/usr/local/bin/perl -w
my $tarPath = "/path/to/place/tar/file";
my $fileName = "/path/to/file";
my $command = "tar xvf ";

$message = system ($command $tarPath $fileName);
if ($message == 0) {
    print "All done!\n";
} else {
    print "Whoops! $command gave exit error: $?\n";
}
[download]

MadraghRua
yet another biologist hacking perl.... ---------------------------------------------------- UPDATE
You might want to stick a my in front of $message to satisfy the -w switch - sorry!