Dear Julien,
Doing business in Pakistan is excellent for those who have investment since there is much opportunities available.
It is not complicated to register a company in Pakistan, there is pre-define procedure and this information can easily be gathered through the website of concerned ministry and departments in Pakistan. I am not sure about cooperate tax rates, but I can claim one thing that foreigners are very happy in investing in Pakistan. Yes, recruiting labor is very easy simply give ads in local newspaper and you fill find plenty of employees who would be ready to serve you.
For advice, I think you should first tell me in what particular sector you want to invest or what business idea do you have??? I may assist you regarding this.
Thanks