There are existing tools for auto generating API documentation - most of the weren't designed for REST services.
For all of you who have created REST services using ServiceStack - how did you write the docs ? Manual / semi-auto / fully auto-gen ? I'm even considering auto gen a customized WADL and connecting it to something like apigee Console To Go
(oh and RESTafaries- please spare the 'REST api should be auto discoverable and self-explained' mantra...I really want nice looking docs for my users).