I have heard about companies setting up wiki sites to allow for user grops to workshare information via the web. When I said something about this to someone, was told it was a lot of work to setup. Anyone care to comment on what is truly needed? The materials needed, effort required, whether it was worth it,...
Figure I need a pc with a network card, and a decent hard drive. Connect the pc onto my network (thus seeing the internet). Then load some software onto the pc/server to manage the wiki content. Voila... a wiki server to collaborate on projects.

A Wiki is very easy to set up. However, before setting one up, you should consider if a Wiki is the right approach. Blogs have gained significant ground over wikis in the past few years. Forums are also good for certain applications.

For Wiki software, I recommend MediaWiki (Free):

Download - MediaWiki

For blog software, I recommend WordPress (Free):

WordPress › Download

For forum software, I recommend vBulletin (Good value for the money):

vBulletin - Downloads

I'm pretty sure there are hosting service dedicated for wikis that if you don't want to get your hands too dirty with physical setup that will work. Say many Web hosts (paid ones) will provide you with access to a portal such as Cpanel that lets you perform a one-click install of wiki software to a web hosting account, leaving you the task of simply configuring the wiki itself.

Yes, I agree that for folks just getting their feet wet in blogs and wikis, a hosting provider is the way to go. Most have easy to use control panels and simple point-and-click installations of web software.

On the other hand, these shared hosting sites can be really slow and sometimes miserable to use.

If you want to experiment with blogs and you are new to the hold world of blogs, I highly recommend a free account on WordPress.com Get a Free Blog Here

WordPress has great software, many cool plugins, the site performs reasonably well, and there is good SEO out-of-the-box.

Really depends a lot on your needs. A simple wiki like MoinMoin doesn't offer a lot of features, but is correspondingly care-free from a maintenance perspective. A more complex wiki such as MediaWiki, twiki, or Confluence adds a lot of extensibility and (through plug-ins, or directly integrated) usability niceties, but also some management overhead. If you're a development shop, I'd also suggest that you also look at Trac, which combines integrated bug tracking, blogging, time tracking (with a plug-in), and wiki in a single package.