Rohani--
We really enjoyed our Colliseum/Forum tour with www.througheternity.com We called them from Rome the day before and they luckily had openings. The tour was 25 euros, and was limited to 10 people.

rohani: This is if you just purchased your ticket in Rome at either of these sites like everyone else.
The Colosseum and the Palatine Hill are the same ticket for the same price.
It is only valid for that day, so you must visit both sites.
Unless it is bought after 1:30pm, then it is valid for that day and the next day *until* 1:30pm.

So what pierreci.it *seems* to be saying is that after you pick-up your ticket and visit the Colosseum. You can also visit the Palatine up until 1:30 the following day.

IMO: I'd pass on this, it's fairly easy to get your tickets at the Palatine Hill.
Sometimes we must make reservations at sites and museums, then we are committed.
But things happen on vacation weather, feeling ill, sore feet, hang-over :), etc. So we either go (misery) or lose the reservation (money).
So why commit yourself when you don't have too? Walk 300m past the Colosseum to the Palatine Hill entrance on Via d S. Gregorio and buy your tickets (no lines at that location).
Regards, Walter

Oops..I may have made a mistake. Our tour might have been with Enjoy Rome. I'll have to double check on this...