Basically, what you need to do to get special provisions at USyd is to go up to Disability Services (Level 7, Education Building) and arrange an interview with them. You need to bring medical proof (HSC things don't count but a specialist's letter does) and they'll arrange a 30-45 minute interview with you.
EDIT2: What I mean by that is that you'll have to go and arrange the interview. They'll give you a booklet on the types of stuff you need to get in your doctor's letter so make sure you fulfil those requirements before going in for your interview.
Generally speaking, if you can't write, they'll give you use of a computer - you get to pick from Mac or PC, depending on which you prefer.
If you have other problems, they can also arrange for things like extra time, rest breaks and the like.
Also, they are quite happy to provide something called the Peer Notetaking Service which will provide your lecture notes. That way you're not disadvantaged from being unable to write and therefore unable to take adequate notes.
For example, I have a lot of psychiatric issues and so I'm on an absurd amount of medication. I basically can't write because my hands shake so badly I can barely hold a pen (side effect).
Disability services are really nice. I've got extended time, use of a computer, no morning exams, rest breaks and the ability to bring food and water into my exams (plus, obviously, I get my notes through Peer Notetaking) - and last semester they managed to get my attendance requirements waived cause I spent a chunk in hospital.
EDIT: Before anyone attacks my special considerations, I'd just like to say that I'd pretty much be unable to attend uni if not for these things. If you're going to bitch at me for them I'll launch into a rather long medical explanation, so, please don't.