Wirelessly posted (BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

If PHX is a valid connecting point on your itinerary, you should be able to get around the four-hours-to-connect rule if you take the last scheduled flight of the day from your origination city to PHX, and connect on the first scheduled flight of the (next) day from PHX to your destination city.

If you take any flight other than the last flight of the day from your origination city to PHX, your stay in PHX will be treated as a stopover, rather than a connection, and this will usually result in a higher fare.