I passed my AIB very recently - if there's anything specific you're unsure of feel free to ask, I can't promise to have an answer to everything but I'll do my best.
As far as general advice goes, just try and enjoy it - and make sure you take the time to get to know the other candidates.
The bleep test, service knowledge and psychometric tests can all be prepared for fairly easily and so are potentially 'easy marks' (maybe not exactly 'easy', but you can improve your chances significantly).
The biggest thing with the PLT - aside from making sure everyone can hear you - is when you are making your plan try to anticipate where you might have problems and come up with some alternatives for those areas.
The interview is similar to any job interview you might go to - just think about what they might ask (along the lines of the questionnaire they send you) and be honest.
There are also several guides/diaries floating around the internet which are fairly useful.
I'd wish you good luck, but if you're relying on luck it's probably all ready too late!
