There are two main aspects to SharePoint governance - IT (server and application) and business. The types of things IT need to govern are vastly different from what business needs to govern. These differences make it hard to compile a governance plan that everyone agrees on.
We have compiled a long version adapted from the Microsoft one, as well as a short version which is adapted from the long one, see links on the right. Both these versions address business governance only.
The respective versions suggest topics to be covered as well as real world examples of each one. These are guidelines only. There is no one-size-fits-all when it comes to governance. Cover the bases that matter to you. Keep it simple, make sure your users understand it, communicate it, do what you say and say what you do.
Consider using a wiki for this instead of a document, it's much easier to keep updated, distribute and communicate. Add a compulsory field on any site request form that they accept and understand the governance plan.
Remember that governance plans affect business users the most, so don't over-complicate it or tie their hands to the extent that it stops them working. They will simply stop using SharePoint.
Regular governance meetings are important to the success of the platform. Weekly, or minimum monthly meetings are a must. (The agenda of these meetings is a seperate discussion).
Plans can be simpler or far more complex. Dependencies include politics, positioning of the product, the version of SharePoint in use, size of company and dedicated SharePoint team. Do what works for you - but just do it.