How can I save money on a flight from Phoenix to Europe?
Good advice so far (except the paper airplane thing). Also, the earlier you can depart in "summer", the more likely you will find a cheaper ticket. Most airlines begin peak or high-season pricing with departures from June 1 (some airlines June 15), so if you could depart the last week of May, or even possibly before mid-June, you are more likely to find a seat at "shoulder-season" prices, since outbound date determines fare (pricing) season.
Also, try other student agencies such as http://www.travelcuts.com and http://www.studentuniverse.com to see if they have a better offer. Student agencies are airfare consolidators who have usually arranged cheaper fees with the airline if you need to change a return date (buy from airline or non-student ticket, pay $150-$200 to change return date; buy from student agency, $25-$75 typical fee for changing return date). If your travel dates are firm, then compare student agencies to published and consolidator fares and just go for whatever is cheapest.
Published fares, including fares direct from airlines, as well as Expedia, Orbitz, Kayak, et al: http://www.bookingbuddy.com -- searches over 40 sources with just one input of cities and dates.
Airfare consolidators: http://www.economytravel.com http://www.flights.com http://www.justfares.com You can also buy a consolidator ticket through a local travel agency, but your travel agent will charge you a booking fee ($25-$40 is typical), plus she really doesn't have much incentive to get you the cheapest ticket since her commission is based on how much the fare costs. Always pay with credit card!
A final strategy: Sometimes it's cheaper to go on two tickets--PHX to LON, then LON to TIA for example. I checked low-cost airlines to Tirana, but the schedules for Summer 2007 are spotty at best, and booking this early, I don't think you could rely on getting a cheap flight from Italy or Cologne (the two places supposedly with low-cost flights from Tirana), so I don't advise a two-ticket method in this case.