I'll be frank the MS documentation for MS web services is terrible / non existent. Do any books exist or web sites that provide full detailed documentation of the usage of SharePoint exposed web services?
Anything specific you are looking for?
Here is something on MSDN - http://msdn.microsoft.com/en-us/library/dd878586%28v=office.12%29.aspx
Typically when trying something I haven't done before I'll open up WebServices Studio (http://code.msdn.microsoft.com/webservicestudio20) and make the calls to see what is passed and returned. This tool makes it pretty easy to get a good look at what is available and how you work with it.