Migrating from ASP.NET 1.1 to 2.0 was a bit harder than most people would
have liked, and because of some of the differences between the two, extra
files were needed for the automatic conversion. If you do a search, you will
find plenty of sites with useful hints for things to remember when
migrating. Something that I recommend doing, however, is instead of
attempting to open a 2003 solution in 2005, create a new project in 2005 and
then do some copy & pasting. This will help you avoid the *.resx files. One
of the other big differences between 1.1 and 2.0 is Partial Classes, which
ASP.NET 2.0 uses when automatically generating the *.aspx.designer.vb (or
*.aspx.designer.cs for C#) files, which contain the declarations for the
controls in the *.aspx file. I am probably forgetting several things, but if
your site is small enough that you can afford to do this copy & pasting, it
may be a good idea. Something else that I have heard (I don't know exactly
how different the conversion is) is that Visual Studio 2008 has better
support for allowing you to open projects from all .NET versions, as well as
converting them and compiling them to different versions (obviously it can't
compile it if it has code that doesn't exist in that version, but you get
the point). Hopefully some of this will help you, and you will probably find
it useful to do the search for sites about 1.1 to 2.0 migration. Good Luck!