I have sat on the sidelines longer than I wanted to but I must input 
here.  Let me state a couple of things.  First, women are not prohibited 
from all types of teaching.  The issue is what they do in the church.  
Let me put it this way, my wife would be teaching boys, if I had any, at 
home.  There is nothing wrong with that.  My wife would also teach my 
children some Bible.  As well, most of us can say that women have taught 
us much about the Bible. 

Yet, the issue is about women teaching men in the church.  That is the 
context of I Timothy 2 when it says:

1 Tim 2:11-15
11 A woman must quietly receive instruction with entire submissiveness. 
12 But I do not allow a woman to teach or exercise authority over a man, 
but to remain quiet. 13 For it was Adam who was first created, and then 
Eve. 14 And it was not Adam who was deceived, but the woman being 
deceived, fell into transgression. 15 But women will be preserved 
through the bearing of children if they continue in faith and love and 
sanctity with self-restraint.
NASU

Now, the context is within a Pastoral Epistle is the church.  Now, 
within that context, we know that women can do some things, like good 
works (see previous verses).  Yet, they are commanded not to teach or 
have authority.  Many commentaries have concluded that in verse 12, 
there is a parenthetical so the verse should actually be read that 
teaching is a form of exercising authority over a man.

Next, I hope we can discuss what we mean by preaching.  For instance, 
there is the understanding that sharing the Gospel is "preaching" and 
there is the understanding that what a pastor does on Sunday Morning is 
"preaching".  Both are not the same type of preaching.  Thus, before we 
could get into too much of a debate we should define preaching.  I think 
all of us would agree that a woman could share the Gospel.  I will 
define preaching is that which is done in II Timothy 4:2, in which there 
seems to be clearly a discussion of what normally is done by a Pastor.  
In that case, the answer is clearly no since a woman cannot "teach" or 
have "authority".

The first objection I believe someone could have is that preaching is 
not teaching.  Yet, I think in context of II Timothy 3:16-17, we find 
that this is teaching of the full counsel of God.

Derick