As far as I know, Apple has never said "you can release code based on
reverse-engineering the iTunes DAAP implementation."  Here's a message
I sent to the daap-dev list (mail <daap-dev-subscribe@develooper.com>
to join).

  From: Nathan Torkington <gnat@oreilly.com>
  To: daap-dev@develooper.com
  Subject: Apple
  Date: Wed, 14 May 2003 12:35:48 -0600

  I spoke to my contact at Apple.  As is usual with Apple, there's no
  clear "yes" or "no" yet.  The big concern for them is that they don't
  want to promise that the protocol used in iTunes 4 will be the
  protocol used in iTunes 5--they don't want people to build software
  around unpublished protocols or APIs and then complain when they
  change.  They want the freedom to keep improving.

  That said, there's a ton of history of people doing this.  The haxies
  are a case in point--kernel tweaks using undocumented APIs.  People
  use 'em, Apple does not feel hamstrung by them, and the developers
  have to play catch-up if and when Apple changes those APIs.

  The contact said that a week was sufficient time to wait for a
  response, after which I can conclude that they won't respond to that
  question.  He's also going to chase down whoever's responsible for
  DAAP and see whether there's anything that can be communicated.

  If I don't hear anything after a week, go ahead and release the code.
  Apple doesn't sue.  If they disapprove legally, they'll send a cease
  and desist letter.  If they disapprove technically, you'll probably
  get email from a developer :-)

  So, short answer:

    If I haven't heard anything by Saturday, it's tacit approval to
    publish the source code.

  Nat