ArenaNet let drop via their blog today that guesting is real and is coming soon. They hinted at this in the blog post from yesterday, but to see a feature so sorely missed since launch finally have an official date is awesome news indeed. The date that guesting is open to all players is January 28th.
This doesn't come without a hint of not so good news. That date also marks the end of free world transfers. This may end up being a good thing for WvW players and we can finally see server populations start to settle and communities really start to form.