This is possible. Word of caution: .NET 2, which is installed by SQL2k5, may very well break some of your applications. Keep that in mind before you install it on the server.
Example: SQL Best Practices Analyzer (BPA) for SQL 2000 will no longer function if you install SQL 2K5 on the server due to .NET 2. BPA is an application that requires .NET 1.1.