Hi, now the Beijing dialect is not the same as before, a lot of idioms disappeared, so the young generation in Beijing tend to speak Mandarin with a Beiing accent.

Here are some idioms in Beijing Chinese.http://www.douban.com/group/topic/3717947/

If you want videos, search for 马季, 郭德纲，高庆海, they are performers with a Beijing or Tianjin accent.

Some resources may not be clear.

Enjoy yourself.  :-D