I'm not trying to be mean, but you're obviously very new to this and you should try to educate yourself a bit about bicycles. One site that a lot of people recommend for all sorts of bicycle related info is sheldonbrown.com. You should take a look through his site and get some insight into the different parts of a bicycle, what makes them work, and how they go together and work together. You don't have to become a bicycle super genius but a little working knowledge will go a long way.

Now, what type of bike do you have? It really doesn't matter a lot in this case since pedal spindles, the part that screws into the bicycles crankarms, are standard from one brand to the next but it may help if you have other questions. If you know what type of pedals you want to mount on your bike you only need to know if the shoe you're looking at is compatible with that type of cleat. Generally speaking, shoe makers make their shoes so that they will accept the widest array of cleats but if you're not positive it never hurts to ask the person who made it or is selling it if the cleat you want to use will fit that shoe. If you want to buy the shoes from Nashbar using the link that was given above you can chat with a representative online and ask them about cleat fit. They should be able to walk you through the whole process and make sure that you get the right shoe at a price you can afford.

As for your original question, having the right shoe for use with clipless pedals will definitely make a big difference. It will allow you to develop a smoother pedal stroke which will allow you to generate efficient power when pedalling. This will make you faster, longer and will really help you when you climb hills that require more power. They take some getting used to for your first few rides so practice getting in and out of them in a place that safe to do so in case you fall over. You will soon find clipping in and out to be second nature.

I hope this helps and good luck with finding the right pedals, cleats, and shoes.

Mike