Hi, I'm not a lawyer but I've watched enough TV over the years to at least give a general answer :-)

So, I think the question you really are asking is what's the difference between a felony and a misdemeanor. They are both classifications of a crime. A felony is more serious than a misdemeanor.

Here's the explanation from Wikipedia, "In the United States, where the felony/misdemeanor distinction is still widely applied, the federal government defines a felony as a crime punishable by death or imprisonment in excess of one year. If punishable by exactly one year or less, it is classified as a misdemeanor. The individual states may differ in this definition, using other categories as seriousness or context."

I should point out that once you're a convicted felon in the United States, you can no longer vote. Also, some States have what's called a "3 strikes" law where, if you are convicted of 3 felonies, you automatically are given a life sentence in prison - and life sentences in the U.S. usually mean exactly that - the rest of your life. Imagine a drug addict being caught and convicted 3 times for felony burglary and then having to spend the rest of his or her life in prison. It happens all the time here...

http://en.wikipedia.org/wiki/Felony

It's also worth mentioning that when you apply for a job - particularly a professional position - almost every employer will ask you specifically if you have been convicted of a felony, and if so, what is the full explanation of what happened. Having a felony conviction makes it quite a bit harder to find professional employment; this is probably the main reason why people try to avoid this if possible. :-)