You will need to do the GRE exams before you can get a PhD in the USA. You'd also need to take some kind of English test and have a certificate ready so that you can prove that you can work in English. To start a PhD in 2009, you'd have to take the GREs this Summer - August/September I believe. Keep this in mind because while most people will be thinking about PhD applications etc at the end of the year, if you need to take GREs then you have to start thinking about it a *lot* earlier. My understanding is that the US Universities will readily give good funding to good foreign students and the VISA applications are given pretty easily to people with educated background (especially if you can get an MSc).