Kolsch is a crisp, clean, easy-drinking ale. It has a straw-yellow hue similar to a pilsner, but is less hoppy, a bit sweeter and uses pale malts and a small amount of wheat. The lager-like characteristics this ale is famous for are achieved by using a liquid Kolsch yeast.
Using White Labs WLP029 and Wyeast's 2565 will help achieve the lager-like characteristics this ale is famously known for.