dial up for net connection

I am giving a complete computer system to a friend. She has both phone and cable sevice. Due to the lack of $S she wishes to use her existing phone service for her net connection. The tower is typical in design and has 2 phone jacks, one "line", one "phone". After I set up the system do I need to do anything tho make the connection work? Does her phone provider need to do anything with her? Do I need to set up a CONNECTION within the OS, XP? I have never used dial up with a tower. I did use it with WEB TV but in that case the connection was automatic once the subscription was in place. Please tell me how it is done in a simple step format. I am a novice. If needed I will let her take care of it. Thank you. Move this post to the appropriate area if needed.