In some cases, the employer will make you sign an English contract in your home country and follow it up with an Arabic contract as soon as you arrive in the kingdom. This could be a bit tricky, so please ensure that your sponsor is a reputed employer. Also, as I have been repeatedly stressing earlier too, do not go by any verbal assurances. There are scores of instances when people have been promised a salary back home and are paid far lower than what they where promised after they arrived in the kingdom :( There is nothing which you can do about it in such cases, because your passport will be with your sponsor and you will not even be able to get out of the country without his knowledge. In short, you virtually become his slave. Of course, this is not to generalize all Saudi sponsors under the same category - there are good employers too and some of them even go out of their way to help their employees.
The contract for an expatriate worker in Saudi Arabia has to be necessarily for a fixed period of time. Make sure that your probation period mentioned in the contract does not exceed 90 days, as required by Saudi labor law. Please note that sick leave and the public holidays for Eid (just after Ramadan) and Hajj holidays are excluded
If you are looking for working in Saudi Arabia, you must be aware of your rights as a worker. The entire cost of bringing you from the home country, visa processing fees, renewal of work visa and the cost of air tickets back to the home country is the responsibility of the sponsor. Do not sign any contract in which you have to pay for these, because it is your sponsor's responsibility to bear these expenses.
More posts will follow about this and other interesting topics on working in Saudi Arabia. If you liked this information, do write your comments here which will motivate me to write more.