Bicycle Mechanics - newbie having trouble with valve stem

I went to Wall-Mart today and bought a tire pump the one with the pressure guage on it. I discovered that it would not adapt to the valve core. The valve core has a stem sticking out that I was not familiar with.
Is it a special adapter that I need to go on the pump or did I buy the wrong thing? Thanks for your reply.

Do you know the difference between a Presta valve and a Schrader valve?

Let me try to be slightly more helpful:

Check out the picture in this link: http://www.sheldonbrown.com/gloss_p.html#presta

Do you have a presta valve (the skinny brass one) or a shrader valve (the fat one like on a car)? If you bought a pump that only has a shrader pump head, you can get an adapter (like on the far right picture) at the local bike shop. They're less than a dollar and they're good to have in your saddle bag in case you need to pump up your tires at a gas station.

No I do not. I must have gotten the wrong pump.

I don't understand. Either you have a presta valve or a shrader valve.

It is a bit confusing but I'll guess he needs a presta to schrader adaptor.

Would Wal-Mart sell a pump for presta valves? I'm guessing no.

Am I right?

Thank you for this information. I bought the pump that fits the schraeder valve. I will get the adapter at a bike shop.

Your pump probably can do both. Did you try opening the end of the hose that attaches to the valve and turning the gasket around?

Your pump probably can do both. Did you try opening the end of the hose that attaches to the valve and turning the gasket around?

good point