How can I get PhD sponsorship?

That largely depends on your nationality and where you want to study. The most likely place to find funding for a PhD is from your own government and you should start your enquires there. FindAPhD's FAQ and funding sections give some information and links, as do some of the discussions in this forum. Many people use this forum to request funding. To our knowledge nobody has found funding this way. If you have an offer of a PhD place, then ask the supervisor if they have any suggestions for funding.