For a very approachable view of Russel's thoughts and work, you can try reading his own writing:
http://www.gutenberg.org/ebooks/author/355
My personal favourite so far has been 'Mysticism and Logic and Other Essays' with 'Analysis of Mind' currently at the top of my reading queue. Not everything he did was like reading 'Principia Mathematica' and his writing is very open, readable and eloquent.