To register the .NET 2.0 reference manual in VS.NET 2008, open the RegisterHelp2.bat in a texteditor and change MS.VSIPCC.v80 in MS.VSIPCC.v90

Do this also in the UnRegisterHelp2.bat. After that, run RegisterHelp2.bat and the help should be available in the contents section of VS.NET 2008 help.