in the dev kit 2 of the servos are continuous and the other 4 are standard servos. If you know what your doing you can modify the standard servos as well.

Exactly, I want to know how to modify the standard servos.

Wouldn't it be cheaper and easier to just buy them? eBay has tons and dirt cheap.... Here is a link in how to modify servos for continuous rotation... Modifying Servos

I suppose..but not quicker.