Moved to the Photoshop Touch forum. This was originally posted in the unrelated Digital Publishing Solution forum.
If I recall, the only way to import your own fonts in either operating system is to either root (Android) or jailbreak (iOS). (They both essentially mean the same thing.) Either requires a hefty dose of tech know-how and would void your device's warranty.
You're better off just exporting a PS Touch project as a PSDX or PSD file and opening it in desktop Photoshop so you can use your own fonts, IMO.