There's a wealth of information at the
Google Group on Polyphasic Sleeping. There are some fairly recent discussions on various ways to adapt more easily, as well as huge archives, a few pages/documents, and links to blogs.
Before I went through my polyphasic sleep adaptation, I got in the habit of napping during the day and staying awake a lot at night. (My husband had been polynapping for nearly 2 months by that time, which made it easier.) I'm fairly certain that the semi-shift in the weeks before made the actual adaptation easier, though there were still some very challenging nights around days 4-6.
Good luck!