Hey,
I learned just about everything I know about MIDI and audio by reading magazines like Sound on Sound, Future Music, Electronic Music and Computer Music.
The best, in my opinion, has got to be Sound on Sound. It's not a production magazine in the sense that it tells you how to make beats, but it does have awesome tutorials on how to really dig deep into your sequencer, it covers mainly Cubase, Sonar and Logic, and I think Pro Tools.
What's also great about SOS is that they post old issues online which you can read for free:
http://www.soundonsound.com/
Click on the articles link and do a search, you'll find a buttload of information.
They also talk about different types of recording techniques, mic placement, and review new and old hardware and software.
Take care,
Nick