Yes, there is a pretty good number of extensibility features that Visual Studio 2008 offers in terms of WCF. Let me outline them for you:
a) Support for "Updation of WCF Proxy References"
b) Support for "Project templates" for WCF.
c) Support for Adding WCF references through the "Service Reference" dialog.
d) Support for WCF Host projects
I am talking about the "WCFSVCHost" executable , the Service host , that can be found under X:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE folder. Search on your search engine for syntax of the parameters that you would need to follow to use this executable.
e) Support for testing Clients
I am talking about the "WCFTestClient" executabke that is also found in the same folder as above, i.e. X:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE. Again search on Search on your search engine for syntax of the parameters that you would need to follow to use this executable
Replace "X:" with the drive, where you have the Visual Studio installed.
Now back to the second part of the question: What is WCF?
Code named Indigo, in its simplest term, can be classified as an Communication API or methodology, replacing Webservices, Remoting, Message Queues and Distributed Transactions.
Third part of the question: "What type of situation WCF will be used"?
WCF or any communication technology similar to it, will be used when you would need to isolate the business logic in a certain layer or server, and provide access to it only through other suitable channels such as windows applications. Imagine a ticket reservation system , a Kiosk ..or any other media that would talk to another server that can interpret the given input , apply the business rules, share the output back. The middle tier is what is going to be replaced by WCF or similar.
And the last part : Advantages of WCF: Let me leave it to you to figure out. Since it does not make sense, if you don't know what gave birth to WCF.
The goal of this whole exercise is to make you excited about WCF only. Hope you are excited about wcf.
That's all what I can think of right now.
And please do not forget to go thru this
MSDN article on WCF. It pretty much covers in detail all that you need.
Hope it helps.