The first leg of rail line is in place since about 2008, and it covers around 20 miles form the airport. It goes out to Mesa and the last drop off is at Sycamore St in Mesa, which is on Main St, and just east of Dobson Rd.
A shuttle takes you to the rail line about 2 miles west of the airport. There are 28 stops and cost is $.75 one way, but you can get a day pass for $3.50
There is no longer national rail service in Phoenix. If you want to catch an Amtrak train you will have to go to Tucson Arizona which is about 110 miles away and a 1 hour and 45 minute drive. Currently a light rail is being built through downtown Phoenix which will extend to Tempe passing Chase Field (formerly BanK one Ballpark) and US Airways arena (Formerly America West Arena). The next extension will go to northern phoenix. But don't hold your breath, it wont open until the end of 2008.
The magnificent Union Station in Phoenix is not in use anymore. Amtrak's Sunset Limited stops in the middle of the desert at Maricopa, 25 miles south.
A metropolis of 3 million people without a rail station... not what one would except in a civilized country!