use XML::Simple;
my $struct = XMLin( \*DATA );
print XMLout($struct, noattr => 1 );

__DATA__
<myconfig_data name="aaa" >
        <level1 my_att="somestring">
                <value>hello1</value>
        </level1>
        <level2>
                <value other_att="bbb">hello2</value>
        </level2>
        <level3>
                <value>hello3</value>
        </level3>
</myconfig_data>