Much of the preview material for "The Doctor's Wife" features a prominent female guest star, and it's clear that the BBC want us to believe that she is the titular spouse. This is going to be a bluff, and the wife referred to in the title will be the TARDIS.
The Doctor's time machine is often referred to with female pronouns, and the TARDIS is the only companion constant enough to be considered a "wife". The message from the other Time Lord is a fake, intended to draw the Doctor to a specific location so that some force can steal his vessel, and I suspect that Amy and Rory will be trapped inside, resulting in a long-awaited explore-the-TARDIS episode.
That's my guess anyway.