I haven't tested it, but you should be able to use the following:

#!/usr/bin/perl

# connect to database ....

my $sql_statement = "INSERT INTO $table (field1,field2)
                     VALUES($value1,$value2)";
my $sth = $dbh->prepare($sql_statement);
$sth->execute or 
   die "Can't Add record : $dbh->errstr";

# Now we can retrieve the primary key that
# was just created in our last insert.
my $table_key = $sth->{insertid};

# or you could use this method which
# is DBI-standard
my $table_key = $dbh->{'mysql_insertid'};
$sth->finish;
[download]

From the Giving Credit where Credit is Due department: I got this from this link.