Well, Pocket UFO is designed to work with hand held devices in general, I have a PDA with it.
Make for the armor and plasma weapons on the research tree ASAP. Just Alien Alloys gives you your first armor upgrade, and it will jumps your survival rate dramatically. Flying suits(AA + Ellerium-115 + Alien Propulsion (+ maybe alien navigation)), are a must late game. Skip the power suits, their not as good, cost Ellerium-155, and the Flying suits are just one more research project away.
Flying suits and hover tanks are about the only thing that will save you from "The Black Plague".
I say Plasma weapons, not because the ammo takes Ellerium-115 to make(ick!), but because they do excellent damage and the aliens will feed you all the ammo you need. Also once you get all the plasma weapons researched you get plasma cannons for your interceptors. Btw, skip the first two new ones, keep the Avenger(They all take Ellerium-115 as fuel, and the Avenger smokes it's predecessors in every way)! The cannons make you practically invulnerable to every thing but a battle ship(very large).
One last note, wile I'm being nostalgic, Even in Pocket UFO, you should be able to intercept UFOs with more then one craft. When the first arrives, minimize the window, and wait for the second to get there. Though in practice, armed with two plasma cannons, one Avenger will kill anything. Even if a battle ship puts it in the shop for weeks.
Edit: One last note, set idle workshops to make Alien Alloys. They turn a fair profit, and are easy to make.