Man:
The scores that are given gives you a projected range that you should score on the SAT. i.e. - 62 on PSAT is equal to 580 - 680 on SAT. That is an actual example given from a report. However, that doesn't guarantee that you'll make within that range.
Personally, my PSAT scores were higher than my SAT scores, but the test itself - if I remember correctly, since it's been the better of two years since I've taken it - should be very similar.
I've recently retaken the SAT, but I do recommend that you start now to take the SAT's if you haven't already. If you want some suggestions, I can recommend them. The farther ahead you prepare, the better you'll do.