Guitar MIDI advice, Line 6 Flextone 3

The MIDI port on this is used to edit and save settings using the software presumably supplied with it. You can save sets of sounds and using a sequencer like Logic would allow you to create a track just to send a program change to the amplifier at appropriate parts of your song. So you can have a complete change of guitar sound with completely different effects come in whenever you like, for example.

If you want to input MIDI notes, you'll need a keyboard and MIDI inteface (although there is a function in Logic where you can play notes on the QWERTY keyboard if you wanted to try it first).

And if you wanted to record your guitar you'd need an audio interface also, I'm afraid (you could try using the Built in inout for starters with a cheap microphone I suppose - it might not be too good but you could build your way up from there).

If you just want to start recording your guitar, have a look at the other Line 6 stuff on their site and look for something that you can plug into your Mac via USB (cheaper than the amp I would think). You'd still get all the great guitar sounds and be able to record as well. I got one of the original PODs a few years ago and still use it often.

Oh yeah - if you get your audio signal into Logic using a USB interface you can record and hear Logic's effects at the same time if you like - the Line 6 stuff has lots of effects capability of its own, but there are things in Logic that you couldn't do solely like that.