Depending upon the crime and subsequent punishment, pleading "guilty" to a crime may or may not be an option. At your initial court appearance, it is recommended that you plead "not guilty" or "no contest" to the crime, so you have the option of building the best defense possible for yourself. If after consultation and reviewing evidence you still wish to plead "guilty," you may do so at the second trial scheduled for you.
Pleading "guilty" to a case is accepted only if the sentencing is only a fine. If the crime carries a jail sentence, the judge will enter a plea of "not guilty" on your behalf, and instead may order you to seek psychological counseling for your crime before subjecting you to punishment. You may also refuse to enter a plea until you meet with counsel before your next appointed court date.
The judge has the option of sentencing you at the initial hearing or scheduling another court date. Sentencing may only occur at the first hearing if you are only facing a fine. If you are facing a large fine or jail time, the judge will usually assign a second hearing, so you may obtain legal counsel and defend yourself in your case. Fines are due and jail time begins at sentencing, unless other arrangements are made.
If you must go to a second hearing, you may be remanded until your second court appearance. There are three different ways to be remanded, depending upon the severity of your crime. You may be free to go under the premise that you will return on the appointed court date. The judge may allow you to go free with certain conditions (such as paying bail and staying away from victims). Finally, the judge may hold you in jail if the severity of the crime warrants it.
Pleading guilty at your second hearing may still get you jail time, or it may give you a reduced sentence to probation, if it is your first offense. Again, your jail time is dependent upon the crime you have committed, though admitting you did commit the crime will appear more favorable in the court's eyes.