Enterprise help desks often rely on Windows Remote Desktop, Remote Assistance, or VNC software to remotely control user desktops. Unfortunately, these options can be difficult to use when supporting home users or computers on different networks or separated by firewalls. I've had very little luck talking a novice computer user through setting up and using Remote Assistance. I think CrossLoop might be a better answer.
CrossLoop is an extremely simple, remote control application that I feel almost any end user can use. And, it's free! I'm sending the link to all my friends and family who constantly ask me to talk them through a computer problem. No more repeatedly asking "What's on the screen now".
TechRepublic Senior Editor, Mark Kaelin has put together a great gallery of CrossLoop that you can see here. You can also download CrossLoop from the TechRepublic Software Library. Give it a try and let me know what you think.