Hi James. A few comments to your question to get things started.
There are a lot of past threads on this topic, and it might help you if you search for some of them.
Which engine is "best" is a bit subjective, depending on your needs. I guess most people want the absolute strongest engine, although I don't understand why it always must be the strongest one.
You didn't mention the operating system of your computer. Windows, Mac, or Linux? At any rate, you'll need a Graphical User Interface (GUI) program to go with the engine.
Also, you didn't mention whether you only wanted free stuff, or whether you'd be willing to spend some money.
I don't know anything about those iphone thingies, except that I know there's a free Stockfish app for iOS: http://stockfishchess.org/download/
Hi I want to download a chess engine onto both my computer and iphone. I want an engine that I can easily set up positions in then the engine tells me what the best move is.
Where can I download this and what engine is the best?
Thanks in advance.