I'm going to Phoenix Arizona this summer and I was curious if anyone knew what sodas I might encounter there. Also, what flavors of Fanta do they have?

you will find pepsi coke mt dew dr pepper 7up sprite a&w jazz sierra mist

Products bottled in AZ would be:
Watt's root beer (only available in small kegs)
Ol Bob Millers white grape, prickly pear, and sarsaparilla. Might want to save these as the plant went out of business recently.
Sonoran root beer at Sonora brewing. might be the same as Watt's, I'm not sure..

Pepsi with REAL sugar (in glass bottles) available at Filibertos.

Also, swing by POP THE SODA SHOP in Scottsdale. They have EVERYTHING. Their website is at Pop The Soda Shop - Over 400 Beverages

Jolt in the bottle cans are also available at many Chevrons in the area