Audiobooks and podcasts can be an excellent way how improve your vocabulary and improve your English. If you are suffering of "written English only" syndrome, this may be an excellent remedy.
What is that funny syndrome ? Many people from information technology (including myself) actually had to learn English twice. During the late teens and university we managed to get reasonable command of written English, so that we could (and did) read the books. Mostly about computers, of course. With that, we managed to build decent vocabulary of words which we knew ONLY in written form, and for many of them have absolutely no idea how this could be pronounced. This had two consequences: we had hard time to recognize the word when we heard for the first time pronounced the way how it should be pronounced - and - which is even worse - often our own audio rendering was be a big surprise to native anglophones :-) ...
During second learning of the language, we eventually learned to recognize most of the words in spoken form and connected the two presentations - visual with spoken. What many people do to make this process faster - and what I did - is to use unabridged audio version of the book and follow along in printed book. Very efficient. You get printed copy of the book and as you listen, you can underline the words that you do not know or find worthy of of getting back to. If you are lazy enough, you can often pick a good translation of the book and look up how did the professional translator translate the word or the phrase.
Because the spoken language is quite different from the language used in books, these two sets of words will never be quite matching. There is however a good common ground between living, spoken language and the technical vocabulary of the books. It is podcast. If you had a written transcription of the podcast, you could do exactly the same thing as with audiobook. Indeed very few podcast have the transcription, because it is quite time consuming and most podcasters are barely covering the cost of producing the audio, but there is an excellent podcast that does have it: Security Now!.
And it not only has a transcription, it an excellent one - almost perfect to the word. You can even choose the format of the text: html, pdf or pure text. You can even reading from Steve's web site and listen to the audio from the same site, all courtesy of GRC.com.
So if you are one of us not born in an English speaking country and want to impruv yer Engrish - go and grab the podcast, the transcript and follow along. There is nothing to loose - the only risk is that you may become very security conscious up to slightly paranoid - which may not be a bad strategy for living on-line :-)
And if you like the podcast or learn anything from Steve and Leo - whether in area of English or computers, look at Steve's product for hard drive maintenance - Spinrite - which pays his bills and makes producing that great podcast possible.