I have been doing some research on this very subject lately, using the Bible, the good ole Strong's Concordance and praying for God's leadership in my study.
I have not completed my efforts by any means, but here are some of the conclusions I have been reaching:
There are other definitions for prophesy besides 'foretell', although that is one of them. (I think some people take that one meaning and use it as a basis for telling people's fortunes, etc.) But another definition is "to speak under divine inspiration." I feel like this definition is more applicable to the kind of prophecy mentioned in 1 Corinthians 14.
To the best of my understanding, preaching and prophecy are indeed different. As stated above, to preach is to "proclaim, declare or herald." On a sidenote, I found it interesting that in the N.T., words such as "preach", "preacher", "preaching" etc. were found far more often than "prophecy" and such related words. Correct me if I am wrong, but Paul never claimed to be a prophet, but a preacher.
At any rate, it appears to me that prophecy is a gift of the Spirit for the purpose of edifying believers, as mentioned in 1 Corinthians 12. Apparently there are those upon whom God moves from time to time, who are not preachers, but who speak in the church as God leads.
Now we must note some qualifications for prophesying. It seems to me that, as tongues must have an interpreter in the church, prophecies must have another person to judge, to either confirm or disapprove what the prophet says. I believe the person who should do this is the one to whom God has given the gift of discerning of spirits as listed immediately after prophecy in 1 Cor. 12.
Furthermore, it seems that women are not to participate in in the type of prophesying that requires being before the church in an authoritative position. (see 1 Cor. 14:34.)
Indeed, one cannot deny that the Bible speaks of prophetesses in the O.T. as well as the N.T. There is even a referrence to this made in 1 Cor. 11, where Paul says that a woman praying or prophesying with her head uncovered dishonoreth her head.
I think it is perfectly in order for women to "speak under divine inspiration" in the church. This is sometimes referred to as 'testifying' or giving thanks to God. But anytime she usurps authority in the church or teaches a man, that seems to be unscriptural.
Now outside the church, it seems perfectly in order for prophetesses to speak to other believers as God may lead her. To be honest, I don't even see anything wrong with a male believer seeking advice from a godly woman who has the gift of prophecy
A few last things I would like to emphasize...
I do not believe any believer should look to a prophet or prophetess more than to God. We all have His Holy Spirit within our soul and He is more than able to lead us individually. We also must beware of false prophets.
Another point is that Paul said in 1 Cor. 14: 36-37 that if anyone thinks he is a prophet or spiritual, he should first acknolwledge that the things Paul wrote were the commandments of God. To me, this implies that we should NEVER place prophesying above the Word of God (the Bible), but we should always esteem the Bible as God-inspired and know that He will never say anything that contradicts it.
Blessings to all of you.