Our new Android phone came with an app called Books that links to our Google Books account.
To add a Siddur to your Google Books account, simple search for:
Standard Prayer Book, Simeon Singer and add it to your book shelf.
Underneath the main link in the Related Books listings you will find links to a dozen or so other Hebrew prayer books with English, German, Dutch or Russian translations or instructions.
They can all be added for free to your Google Books account.
Then open your app on your Android or iPhone and go ahead and pray.
We have a great new Samsung Epic 4G Android phone, loving it.