Taking your queries one at a time:
can any of you give me advantages (and advice) in doing ipt in yrs 11 and 12?
Read ahead, definately.
Memorise definitions
Do your homework and exercises
just asking cause i'm not sure if all saints senior let me change subjects after two weeks
They should let you, as my school would let people change, if there were enough numbers in the other class, and if it didn't clash with any other subjects you were undertaking.
also are there any reliable textbooks for the course in yr 11?
Gk Powers - Preliminary IPT textbook
This is your new holy bible to IPT
When I did year 11 IPT, I wanted to purchase the excel IPT guide, which wasn't in production/printing at the time, so the earliest print run had been Sept 2003 or so, after my course finished (preliminary)
I ended up buying Excel HSC - year 12, and it wasn't all that useful IMO, but still good to have -- if you've bought it, you might as well use it, right?
As far as Year 11 goes, it should be an easy ride for you, just don't slacken off at the end thinking you're going to ace the course and whatnot, because the HSC course is more difficult than the prelim (which makes sense), and relies on your preliminary knowledge to progress onto the HSC course.
good luck with the studies, and if you're finding IPT boring, etc - think seriously about dropping it or continuing, as you'll benefit either way (depending on how well you are as a student, etc)
all the best freakstar