I think Pearson will release the testing dates for 2012-2013 after all the PCAT testing for this cycle (2011-2012) is done. So check PCAT website again in April/May 2012?
Now that PCAT is computer-based, you receive your preliminary score report right after the test if you choose to score (July 20 PCAT testers are waiting to see if those preliminary scores mean anything). You can check your official PCAT score online about 5 weeks after your test.
If you would like to receive your PCAT score by fall of 2012, you should take the PCAT in July 2012 (assuming Pearson doesn't change the PCAT testing months). If not, most Pharmacy schools do accept September scores (some even accept January scores). You should take the PCAT a year prior to your desired entering class year (ie. If you want to matriculate for Fall 2013, you would take PCAT in summer/fall of 2012).