I haven't gotten to the point where David is, but i'm trying (leopard isn't "approved for use" in our organization yet, they expect it to be in a few months, but i can still use it at home :).
something to add to the knowledge base (although pretty obvious, it stunned me this morning): if you are upgrading a Tiger machine that had xcode installed on it you must upgrade the xcode tools too, or you won't be able to link any binary from p9p. xcode is available on developer.apple.com or on the upgrade dvd that has leopard.