How can I log on remotely from my Macbook Pro to a friend's iMac so as to share her screen, and help her fix things when she has problems? My own knowledge is not very profound, so please bear that in mind with your answers. I am somewhat more at home with Unix than with Mac Os, but still no expert.
I realize that I would at least need her Mac's IP address. However, I think her computer gets its IP address from DHCP, so it would presumably change every time she turns her computer on or off. I suppose she could email me the IP address when she has problems, but that's not ideal.
Do I need to buy software for this task, or can I manage with facilities provided as standard by Apple? Does it matter which OS we work on? I am still working on 10.6.8, and I'm not sure what her iMac is running.