We have a project server and I was asked to investigate the version control capabilities of the server. After doing some Googling on the subject, I was able to find an article that walked me through how to enable document version control on a sharepoint 2007 document library. It was actually very simple. All I had to do was on the root of the document library, click on settings. The link for the settings of the document library contained another link for version control settings. I clicked this link, turned on major and minor revisions and selected the option to force checkout when editting a document.
The neat part is, when a user opens a document for editting, it will automatically checkout that document (to prevent others from editting it). The other cool part is it saves a new minor revision every time a user saves it, also giving the user the ability to insert comments. It shows which user editted it, what time it was editted, and a slew of other information. The major revs are controlled by users simply selecting "Create new major revision" from a pulldown menu on the sharepoint site when looking at the document.
I think its very solid document management. Very intuitive to use. I have to admit, Microsoft actually did something right. If you know me, I typically am on the Microsoft hate bandwagon, but the project server product with sharepoint version control is pretty sweet.