>I will be installing Visual Studio 2005 on a development computer (Windows xp pro) that already has VS 2003 installed on it. I'm assuming this is ok, but does anyone know for sure?

Yes VS.NET 2005 will not effect anything in VS.2003.

>Also, I will be installing Sql Server 2005 Developer's Edition on the same machine, where sql server 2000 Enterprise Edition is already installed, and want to keep both versions there, rather than upgrade the old sql server to the new. I'm also assuming this is ok, but, again, does anyone know for sure? And are there any gotcha's on these issues that I neeed to know about?

Yes that works too, although you'll have to reference the 2005 version as a named instance.

+++ Rick ---