Nigel's right, it's simply not possible to do with a PIC, it DOES NOT have the required hardware to act as a USB host.
There are some standalone chips which can perform USB host duties, however they are all certain to be pretty complex and hard to use. Plus, not many hobbyists have used them, so you're probably not going to find many (if any) example projects to work from, and not many people will be able to offer much help - since it doesn't appear you even did your basic research before posting this thread, you may want to SERIOUSLY reconsider what you're trying to do...