how to make them like this?!

I would use a white cake batter, then add certain colors to specific batches. You can just use food coloring for this. :) Then for the frosting...you can just add a little red food coloring to white frosting so it comes out pink. Or you can just dye the sugar with red food coloring, and sprinkle that over the white. Hope that helped. :)

You add food coloring to the different batters to achieve the colored cupcakes. When it comes to the icing, it looks like a light pink or white icing, covered in pink and clear sugar sprinkles.

Loads of food coloring and white frosting covered in pink colored sugar sprinkles. The cake batter for the cupcakes will need to be white.

The cupcakes have a few drops of food color added to the batter to tint them before baking them. Theses CUPCAKES are AWESOME.
Here is a link for the cupcakes:http://ca.images.search.yahoo.com/images…
You need to scroll down until you see the recipe as I have put it in for you already, but the picture is there.
Rainbow Cupcakes
First, you need to mix up the batter for plain vanilla or white cupcakes. Divide batter evenly into 5 small bowls; each should have a little more than 1/3 cup batter (approx 6 tbsp or so for each).

Add about 1/2 tsp food coloring to each bowl to make red, orange, yellow, green and blue batters. Stir well, so no streaks of plain batter remain. Vibrant colors are the best thing about these cupcakes, so don’t be afraid to add a little bit extra food coloring if you don’t think that yours are strong enough. (Gel color works great too.)

Starting with whichever color batter you would like too, add a small spoonful to each of the cupcake liners (just over 1/2 tbsp in each). Repeat with all remaining colors, adding each spoonful on top of the previous color. You may need to use spoon to help spread batter out, but be careful not to blend colors.However, if you do not want a layered look or get tired of the whole layering thing, just spoon batter in randomly all over to make it spotty. Every cupcake will be different :)

Bake for time indicated on cake mix, or until a toothpick inserted into the center comes out clean.

Cool cupcakes on a wire rack before frosting.
As for the picture of the iced cupcakes, they are iced with a white butter cream icing, probably using a tip to swirl the icing onto the cupcake, and then dipped into a cup of pink large grain sugar crystals and shaken off. The sugar crystals can be found in a Bulk Barn or bulk products store.