If you're just starting out and are concerned about shoes you can also walk in then consider mountain bike shoes to go with the pedals. If you want road shoes however you can buy adapters for some shoes (I know Sidi has them for Shimano SPDs). If you know what brand they are check the internet for compatibility as there are different types of MTB pedals. I would recommend just getting road pedals if you're interested in road cycling, especially if you're not planning on doing lots of walking in the shoes.