What tools do you use to share knowledge amongst developers in your company?

I'm looking for some good tools that help to share tips, best practices, company standards, etc. amongs developers in my company. Two tools I'm currently considering are a wiki (screwturn wiki) or Sharepoint 2010. I'm wondering if there is something better suited to the task, or any input anyone has on this subject. I'd prefer something that's windows based (i.e. runs on IIS, can authenticate users against Active Directory etc) but I am open to anything.

Well, you're right, the most suitable computer tool is Wiki. There are many engines available. We use Atlassian Confluence. It is good to write down things that contains many formal details. Like client-server protocol description, or game-design / UI-design documents.

However for sharing tips, best-practices, interesting investigations etc no tool will overcome live talk! I've came to this conclusion for many times. Daily standups and pair programming lead to much much better information circulation than any computer-based tool I ever seen.

At my company we use a private MediaWiki installation. It works very well for our needs.

Publicly we share programming knowledge at DocForge.