Hi michael,
It must be painless, at least until now I have had no problem doing so, the
biggest solution that I "convert" was one with 4 projects and it was a cake.
Now the "should I upgrade?" thing is another thing, if the project is being
developed without problem or you do not need a feature found only in 2003 I
would stay with 2002 until the end, or at least until reach a safe stage.
AFAIK the code written for 1.0 will work without any change in 1.1 , maybe
you will get new warnings for methods that are obsolete ( like TcpListener
Constructor (Int32) ) .
You could also do that on a copy in another machine and see how the things
go by.
Hope this help,