i want to know that if i am looking at any page on internet which has the extension .aspx Is that page developed in asp.net ? and braodly is asp nd asp.net same thing?
ASP and ASP.NET are two very different things. ASP.NET is successor of ASP. ASP is now old and out-dated. ASP.NET 2.0 was released in November 2005, and it lately got a substantial extension in form of ASP.NET AJAX release. ASP.NET provides by far more programmer-friendly approach. Additionally, one can use free version of Microsoft's IDE.
ASP.NET is the Friggin Bomb! (Just had to throw that out there) I would stay away from classic asp if you have the chance... theirs a lot of hidden nuances you need to know (like sql injection protection and form hijacking protection)