<p>I have seen <a href="http://blogs.msdn.com/djpark/archive/2007/11/07/how-to-use-solutions-and-projects-between-visual-studio-2005-and-2008.aspx" rel="nofollow noreferrer">Solutions created in Visual Studio 2008 cannot be opened in Visual Studio 2005</a> and tried workaround 1. Yet to try the workaround 2. </p>

<p>But as that link was bit old and out of desperation asking here: Is there any convertor available?</p>

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<p>I dont have VS2008 yet and i wanted to open an opensource solution which was done in vs2008.</p>

<p>Guess i have to fiddle around or wait till the vs2008 is shipped.</p>

I'd say you should restore your 2005 version from source control, assuming you have source control and a 2005 copy of the file.
Otherwise, there are plenty of pages on the net that details the changes, but unfortunately no ready-made converter program that will do it for you.
Be aware that as soon as you open the file in 2008 again, it'll be upgraded once more.
Perhaps the solution (no pun intended) is to keep separate copy of the project and solution files for 2005 and 2008?
Why do you want to open it in 2005 anyway?