According to an article that I came across recently, The Dangers of Joint Accounts, having a joint account doesn’t mean that inheritance money will remain in your hands when your parent/spouse/other joint account holder dies or the inheritance you are leaving will go into the right hands. Having a plan in place and having a clearly identified legal will can help ensure that your wishes will be carried out. Remember to keep your will and other associated documents up to date with any changes along the way (for example, if you decide to give one of the willed items away early remove that item from the will).

Wikipedia gives an outline of what a will or testament is and what it’s requirements are.