This advice comes from a variety of my experiences: working in lots of offices, being an office manager and interviewing people, and what I know of employment law (I just graduated from law school and I'm not a lawyer yet, so this is NOT legal advice, you should consult a real attorney for that, blah blah blah...
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DO NOT LIE. However, you should definitely put some seriously positive spin on the situation. You probably don't want to leave the job off your resume, especially if you worked there awhile - it would be a big hole and look like you didn't work.
If asked about why you left your previous position, say something like "I enjoyed the work at first and learned a lot at XYZ Co., but in the end we weren't a good fit and now I'm looking for a position that's more [whatever you're looking for]." Then MOVE ON. The important thing in any job interview is that your time is limited and so you don't want to waste time on negatives. If it does come out that you were fired, make sure to let the interviewer know that it wasn't because you did anything horrible (i.e., it wasn't for embezzlement or blowing up the building), it was really a simple difference of opinion, you've learned from the experience, etc. and MOVE ON TO SOMETHING POSITIVE.
Now, here's a little insight you may not know: I would bet that if an interviewer contacts your previous employer, they're not going to say anything bad about you. Not if they're smart. Your state laws will determine what they can say, but they will most likely say much less than the law allows. The danger of lawsuits has scared most companies so now all they will do is confirm that a person worked for them and the dates. Therefore, if you don't tell all the dirty little details during your interview, chances are, your previous employer won't either.
One strategy to consider is getting a friend to pose as a potential employer and call your old boss and ask about you. A little underhanded, but it's one way to know for sure what they are saying. Just don't play too many games - i.e., just get your friend to tell you what they said, don't listen in on the other line and then yell "Busted!" at them if they get nasty.
Finally, remember that LOTS of people get fired for LOTS of different reasons, and it's not the end of their life or career. You are young and have lots of opportunities. This is just a little bump on the road.
Best of luck to you!