The content is broad, but lately I've been reading ryanholiday.net. While he's not really a philospher or psychologist, his content is strongly influenced by both disciplines. I've also been following BJ Fogg and Kelly McGonigal, both of whom are psychologists at Stanford, the former studying persuasion, and the latter studying the science behind will power.

I tend to read a lot of psychology and philosophy blogs. Of course, I'm also interested in my own content which is along the same lines: http://agaponzie.blogspot.com/2012/07/developing-will-power....