Any large scale development process will encounter conflicts which must be resolved. Often resolution is an arbitrary decision in order to further progress the project. In commercial teams, the corporate hierarchy + performance review structure solves this problem -- How do OSS teams resolve them?
In the case of Linux, Linus Torvalds is the undisputed `leader' of the project. He's delegated large components (e.g. networking, device drivers, etc.) to several of his trusted "lieutenants' who further de-facto delegate to a handful of "area" owners (e.g. LAN drivers).
Other organizations are described by Eric Raymond: http://earthspace.net/~esr/writings/homesteading/homesteading-15.html:
Some very large projects discard the `benevolent dictator' model entirely. One way to do this is turn the co-developers into a voting committee (as with Apache). Another is rotating dictatorship, in which control is occasionally passed from one member to another within a circle of senior co-developers (the Perl developers organize themselves this way).
That's what the infamous Halloween Memo has to say on the subject:
http://www.scripting.com/misc/halloweenMemo.html.
