Sitecore Basics

I am quite new to Sitecore WCM and have been doing a lot of research and readings. Could someone please help me to clarify the following basics of Sitecore?

I’ve a number of ASP.net web applications. If I convert the project to Sitecore project will it just work magically?
If I want to create new site, do I need to manually create a new site in IIS or Sitecore does it when I publish?
Are there any online training videos available, could not find a single (except Sitecore marketing demo).
If we have MVC and Web forms applications, is it possible to migrate to Sitecore?