I saw some social networking like sites applications database listed on
dbo.aspnet_profile
dbo.aspnet_roles ect..
folders.Is this a default membership or What you guys call this ? Is this call a memership provider ?
Here i have attached image for more illustration

Is thisone available in .NET Framework 4.0 ?
This is called ASP.net membership.
ASP.net Membership was released in .net 2.0 but is still current and can be used with .net 4.0.
You can install it very easily. Instructions
You will need to understand how the database is designed. Relational Diagram
Finally here is a good instruction video.