Shoe/Shirt Size clickable list instead of drop down menu

[Ranaly]

I'm stuck here. I'm trying to create code that will list out all of the available sizes for the item without using a drop down. In the two links below you will see what I am talking about. Any items that are out of stock are grayed out and when you click on an item in stock the item availability comes up in red below your selection. Can anyone point me in the right direction (maybe a tutorial) in how to get this done? I'm trying to implement it in my magento site. Would I need to use php or is there an option in magento?Shoe Examples:http://www.karmaloop.com/product/The-AR-20-Sneaker-in-Craft-Blue-Running-White/263936Shirt Examples: http://www.karmaloop.com/product/The-We-Win-Hoody-in-Black/271919