running asp dot-net application on different platforms

[z. f.]

Hi,

I have asp application running on windows 2000 sevrer, that i'm upgrading to
dot-net.
in the process of upgrading the application to dot-net, there will be a
period that my dot-net application needs to run on windows 2000 server, and
after it on windows 2003 server.
there will also be a period that the asp dot-net pages will need to run on
both windows 2000 and windows 2003.
if there any problems i should expect, or configuration problems (few i
already noticed, like xml server http request) i should get ready for?

TIA.