1- Start with downloading this archive :

CompileWithDotNet11.zip

2- Check the requirements :

Visual Studio 2005, C#
Framework .NET 1.1
CompileWithDotNet11.zip (cf 1!)

3- Follow the instructions :

- Copy ‘DotNet11Compile.CSharp.targets’ to C:\Program Files\MSBuild (This file was initialy built by Jomo, I have just changed 2 lines : http://blogs.msdn.com/jomo_fisher/articles/410896.aspx)
- Open Visual Studio 2005 and create an empty C# project (console, library, winform, …) or open a old Visual Studio 2003 C# project and accept the convertion
- Save it and close Visual Studio 2005
- Open the .csproj file with notepad
- Change the following line
 
 <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />

 by

 <Import Project="$(MSBuildExtensionsPath)\DotNet11Compile.CSharp.targets" />

- Re-Open the C# project
- Open the Configuration manager (Right-Click the solution and select it in the menu or open the ‘Debug/Release’ drop-down list en select it)
- Choose ‘New’ in the ‘Active Solution Plateform’ list (Current selected value should be ‘Any CPU’)
- Select ‘.NET 1.1′ and validate
- Build
(If necessary, correct errors on lines like ’using System.Collections.Generic;’ by commenting it and rebuild)

The archive ‘CompileWithDotNet11.zip’ contains a sample C# console project.