I'm in my 2nd period web design class, and I am showing my students how to blog.

I've been using TypePad since they opened business.  They are not free, but I always free you get what you pay for and I have with Typepad.  It's easy to use.  There are lots of different ways to post entries. You can do it on the web, with your mobile phone, with the ipod with an app, (probably with the iPad's, but I haven't tried it). 

There may be an android app, I will have to look but you can certainly do it in Chrome on any Android device.

There are lots of Window's clients and you can even blog in Word, but we're not real happy with it.

Typepad is at http://www.typepad.com and also linked to my site.