Yes you have heard right Dubai is tax free, if want to work in Dubai your salary will be paid to you gross no personal tax or working tax will be taken from your salary. Direct personal taxation is against the law in Dubai. This also applies if you have a home that you are renting out to locals or foreign who lives in Dubai.
The current status in Dubai regarding tax, there are 15 free trade Zone and more in the planning stages, the free trade Zone is where foreign businesses can established themselves and grow as for this benefit of free tax the companies offer the same benefit to their employees where the salaries of the employees are also tax free.
To work in Dubai you need a work permit and residency visa, but the majority of employers arrange these requirements for you as you sign the contract you will get the work permit automatically as well as the residency visa. Some travel to Dubai using a temporary visa and then as soon as they find a permanent work they apply for work permit and residency visa if the employer doesn’t provide it themselves.
Staying in Dubai with a temporary visa and how long you can stay in Dubai depends on the country you are from and you can check the UAE embassy which rules applies for you before you travel to Dubai.