Answers:
I agree with Lynn, who indicated that you have to buy them.
I would suggest http://www.sats-past-papers.co.uk... is also a good place to get them. They supply different levels at Key Stage 3, covering Mathematics, English and Science, which I guess will be the ones you will be taking in May 2007.
You will need to know what levels you require, as you will be sitting a paper which is appropriate to your ability. For example, KS3 Maths has four levels, 3-5, 4-6, 5-7, and 6-8. You will only be taking one of these papers in May 2007.
For Science, there are two levels, 3-6, and 5-7, and again, you will be sitting the paper appropriate to your ability (about 50% of UK pupils sit the lower paper, 4-6, and about 50% take the higher paper, 5-7).
In English, there is only one level, a 4-7, but there is also a Shakespeare paper, and this year there is one of three plays you might be sitting, Much Ado about nothing, The Tempest, and Richard III.
If you need them quickly, their homepage states that they send all orders placed before 3pm the same day!
Good Luck.