Almost everyone has this problem. From what I heard the reason why it takes so long is when there are errors in the games or updates that were installed it takes longer. One way around it all is to manually delete all the games from your iphone that you do not have saved files for (keep the games on that you have saves for and delete the rest) then sync. The backup should be quicker but you will then have to reinstall all the games you deleted from your library.
wow my backup is alot faster than the first time around, guess it depends on the amount of new memory to backup.
