Which online shopping website for example, Hot Topic. But I want
a website that has metal/rock band t-shirts for kids around 10~12.
And the site needs to include international shipping.

Here is a reputable site with rock/punk clothing for Kids available:
http://www.punkbabyclothes.net

You can view the international shipping options on their site by going here:
http://www.punkbabyclothes.net/shipping.html
If you don’t see the country that you need on their shipping list, you can forward your items through a forwarding service that has shipping to over 223 countries worldwide.

Here are a couple of forwarders to check out if need be:
http://www.bongous.com
http://www.usa2me.com

There is this commercial on tv sometimes (Vh1 maybe?) and it’s of some band that is talking about their favorite songs. It is some website like zentunes….or something.
Thanks
I’m not sure about the site you are talking about, but iTunes has many celebrity playlists here:http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewCelebritiesSeeAllPage