Urdu came into existence by the combination of all languages that of period. It is spoken in all parts of the Subcontinent due to this reason. \rdu spoken in India is not very different from Urdu spoken in Pakistan.
The difference you would see, would be mainly because that in Pakistan the medium of education for a large number of people is Urdu… so if a non-Urdu speaker (like a Punjabi, Pathan, Baloch or Sindhi) would speak Urdu, it would very much influenced by ‘kitabi’ Urdu… which a puritan would call ‘translated’ Urdu. They would be not very generous with using metaphors, sayings and idioms. The same thing is seen in their written Urdu, though to a lesser extent.
Many of the people answering here has said that Urdu in Pakistan is influenced by Punjabi. I do not think it is true. The truth is other way round. Punjabi is much influenced by Urdu. Punjabi-speaking writers of Urdu has enriched its vocabulary a lot but they have not affected its syntax. True that some people would say ‘main ne jana hai’ instead of ‘mujhe jana hai’ but sooner or later they would be corrected by someone more educated.
Don’t go by the Urdu spoken in Pakistani media. Many of the media persons are young people educated in English medium and their foundation in Urdu is not very strong. If you want to hear good Urdu, watch Pakistani tv dramas of 70s, 80s and 90s. You will not only find good Urdu, but also see how regional differences affect the accent. A drama for Quetta (Balochi, Brahvi influences) or Peshawar (Pashto, Hindko influences) center of PTV would sound differently. Lahore center would have its own color (Punjabi, Pothohair, Saraiki) and Karachi center would provide the purest form of Urdu spoken in Pakistan, along with the Sindhi influences, as the writers their are native speakers of Urdu or Sindhi. Television dramas of today are not a very good indicator of the Urdu spoken in Pakistan, all of them seem colored in the same shade.
Look out for dramas like Waaris, Samandar, Raat, Khwahish, Pyas and Din (Lahore center) and Ankahi, Tanhayian, Khuda ki Basti, Aakhri Chattan (Karachi center). All of these are available on Youtube with many more.