Hey J,
ASP.NET "should" be compatible with Netscape. The reason I think this is because there is no more vbscript per se. All of the coding is focuses now on code behind files that hold vb.net code, and which the server processes. Therefore, all that comes back to the browser is pure html, and script language isn't an issue
Now, with that said, you should still probably test it out. But I can't see the same browser-incompatabilities happening.
Jack