Oral wills, or nuncupative wills, are permitted in many states under limited circumstances. However, a form of guidelines should be utilized if you are planning on making an oral will to be assured that it will be honored.
If for some reason you do not wish to make a written will (which is always the best choice), then you should be familiar with the guidelines and provisions should you find yourself in a situation where an oral will is the only choice available. These wills can usually only be used to dispose of personal property, however a few states will allow real property to pass under these circumstances. It should be noted, however, that the Uniform Probate Code does not make provisions for these wills and some states do not permit them. Generally, oral wills are only used if they are made by someone who anticipates death from an injury received the same day, or if made by a soldier in the field or on a ship who faces peril and death. Many states will recognize an oral will made by military personnel under these circumstances. The oral will must be heard by at least two individuals who are disinterested in the assets or distributions of the same. Many states require that oral wills, or nuncupative wills, be written down by the witnesses within thirty days and probated with the courts within six months of being given. Therefore, oral wills do serve a purpose in emergency situations, but the person giving one should not rely on the fact that their wishes are going to be honored in all circumstances. As always, a written will is by far the best choice, but not always available.
You can find a great collection of legal will forms on various legal form sites.