castillian ronunciation
http://wikitravel.org/en/Castilian_Spanish_phrasebook#b do peaple of northern Madrid really pronounce there j g d like that
2 Answers
peaple of northern Madrid
Throughout all of Madrid, in fact, throughout most of the northern portion of Spain.
P.S. The description of the sound of the "jota" is wrong in that article (which claims it sounds like the "ck" in "block") a better description is given for the 'g' before 'e'/'i' and that is the same sound that the "jota" has.
Many do, yes. It's a fairly common pronunciation in my experience, and it is how I speak more or less.