Everything ausgirl said!
Some banks will do a 'no deposit loan' which sounds appealing to some, but it's not. And usually with those deals the interest rate is higher. The more deposit you have, the better deal you can get, and the less you pay in the long run.
It's best to go to a mortgage broker so they can shop around for you to get the best deal for YOU.
Also, have a good think about what can afford, taking into consideration interest rates increasing as well.