Integrating ASP.NET 4.0 application with SharePoint 2010

Hi I have an ASP.NET 4.0 application which I want to integrate with SharePoint 2010. I saw an MSDN article http://msdn.microsoft.com/en-us/library/cc297200(v=office.12).aspx which applies to MOSS 2007. The same can be done using SharePoint 2010? Also do I have to change the framework of the asp.net application to 3.5 before doing this?

I have read a couple of other links too which does this with seperate virtual directory and app pool like 

http://www.ericjamesw.com/2012/12/adding-aspnet-40-application-to.html

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