Which server (or PC?) can the schema (setup /pl, etc.) be ran from?

Obviously, the schema must be extended from a 64 bit server which rules out running it from my existing, Exchange 2003 server, right?

My new server that will host Exchange 2010 is a 64 bit server - it it O.K. to extend the schema from it, or do I need a separate, 64 bit server (with the AD tools installed on) to run my setup commands from?

I also have a Windows 8 PC (that's 64 bit) - can I extend the schema from that machine (or is that a bad idea?), or should I just perform the commands from a server?

Suggestions?

Ed