Hi, it pretty much involved what's been said before in this thread. There are 4 multiple choice aptitude tests, firstly maths, followed by abstract reasoning, mechanical reasoning and spatial awareness. It is pretty tough to finish all the tests in the time given, it is more important to work accurately and leave a few unanswered then rush.
The personality questionaire asks you a series of questions such as "have you ever taken advantage of someone's good nature", honesty is the key as these tests have been designed to catch out liars.
To prepare I bought the Times pscyhometric CD-ROM and got a few books out of the library that featured such tests and practised. Definately worth getting a maths book out and brushing up your algebra too.
Best of luck!
