Hi There,
Go to www [dot] pearsonvue [dot] com and sign up for a web account. When they email you your username and password log into Pearson Vue and Select your Country, Exam etc and it will take you through a whole process in which you can view you exams price, book a
test center and even pay online with a credit card.
If you don't come right just phone Pearson Vue and they should be able to direct you through the whole process.
Hope this helps. Sadly I had to make loads of calls and queries before I worked it out. There is no clear help on Oracle's website regarding individual exam bookings.
Good Luck !
I write on the 9th of Feb. Hope I pass xD