All the previous posts are 100% right on. Flyboy's description is pretty much what you can expect for you CFII training. YOu could probably do it in as little as 3-5 hours if you are instrument proficient. My CFII checkride consisted of myself doing an instrument approach from the right seat, and the examiner doing an instrument approach, in which I had to cover up his instruments, and give him an engine failure during an approach (the ride was done in a Seminole).....and that was pretty much it.
As a CFII, I've signed off someone for their CFII checkride with just over 3hrs of dual given. Granted, I knew this student very well, and he was very proficient, but it just shows you it can be done in very minimal time.
Also, a helpful hint. If by chance you can do your CFII ride with the same examiner you took your instrument checkride with, it usually helps. If the examiner remembers you, your oral tends to be shorter because he/she will remember your instrument checkride and won't ask you the same questions over again.
Good luck!