You probably have a strong urge to pick up the phone, call the lawyer you met, and ask what is happening. Before you do that, however, you need to do some homework. If you know others who have interviewed at the firm, talk to them about their experience. If not, the firm may well simply be slow in getting around to making a decision. Firms vary in the speed with which they make hiring decisions.
Some firms are more cautious than others.
In addition, you may have been interviewed early in the recruiting season and the firm is continuing to make its rounds of law schools. Whatever the reason, months may go by with no word from the firm. There is very little you can say during a telephone call that is likely to arouse greater interest on the part of the firm than you will be able to generate during the interview at your school. If you cannot suppress the urge to contact the firm, write them a letter indicating how much you enjoyed the interview and look forward to hearing from them. Even if such a letter doesn't help your case, it may make you feel as if you are in greater control of the situation.