Fantasy Baseball League Management

I have run a league this year using the Fantasy Yahoo stuff and it was
adequate for what we were looking for. There is a group of us here
(14) at my job that participated and enjoyed this season. However,
while it is still fresh in our minds, we are looking for something a
little more extensive than what Yahoo offers, so I thought I would
post here and see what people recommend. We are looking for something
that can be run on a web site. I already have my own site and
hosting, so I do not need something hosted somewhere else, but I am
not opposed to that either. If anyone has any suggestions, I would
love to hear them.