Advice on getting a wiki up quickly?

[MH1]

Hello friends, I hope someone will give me some good advice:

I've built basic websites before and know databases (Access, Oracle, MySQL sort of) but never put the two together before. Now I want to quickly get a wiki up and running that will allow about 50 people (to start) to collaborate on building a knowledge base on a specialized topic.

I already have a domain registered, I've edited wiki pages before so I know how it works from the user side, and I have knowledge management backgorund so I have the conceptual foundation of what I want to do. I can do light coding in several languages; I'm game for a challenge if necessary, but I'd like to get the tool up quick.

Any thoughts on

* the best wiki software for a novice implementer to use,
* whether I should get Linux or Windows hosting (my desktop OS is Windows, but I don't care much for MS in general and Access particularly, so am leaning Linux for hosting unless someone waves me off)
* what else do I need to be thinking about on the technical end, especially in selecting a hosting service?

Or does my question show me to be a total fool who should just forget it and take up golf instead?