At this point in time Software updater won't give you the option to upgrade to Saucy, so you'll have to change the repositories from Raring to Saucy. The easiest way is to use this command in a terminal:
Code:
sudo sed -i 's/raring/saucy/g' /etc/apt/sources.list
The other way to do it, is to open /etc/apt/sources.list in gedit:
Code:
gksu gedit /etc/apt/sources.list
and use the search and replace function to change raring to saucy. Using either method won't change the ppas from Raring to Saucy, which is probably for the best, as they aren't usually updated to Saucy until it is released.
Unless there are some really major changes to the distribution, it won't make any difference if you use the raring ppas instead of the saucy ones.