Yes, I went to a STAT workshop by the WEA Sydney institution. There should be an ad in this year's UAC guide (there was in mine, the 2005 one for 2006 uni entry) telling you more. I found it alleviated my panic, but in the way of actual solid preparation--not really. The STAT was designed for mature age students who have not had academic stimulation in some time and would like to enter uni, so they just go through some strategies on how to attack the MC, and give a lot of practice questions, but yeah, it's mainly your skill so it's up to you. If you are capable of getting into pharmacy (which I'm assuming you are doing), STAT will be alright, I promise.
As for timing--if you sit RET, you will receive a letter if you are eligible. But if you're looking for STAT, watch out for that. I would advise you do it after your HSC--there's something like 5 sessions between the end of your HSC (assuming you finish 3 weeks in) and the deadline for the STAT test attempt to be considered as part of your application, so there's really no rush. Remember though, to link the test attempt to your application--that's really important. And um, yeah, in comparison to UMAT, it's easy.