Screen sharing type collaboration is a common need. Mostly I use LiveMeeting, but it does require the other person to install the LM software and then you send the invitation. I was looking for something easier to install/set up, and ran across Join.Me from Logmein. It works on PC’s, iPhone, and Android, and it’s a dream to set up. No registration, just start a session.
The free version doesn’t have the bells and whistles of LiveMeeting (they do have a Pro version that comes closer), but it’s, well, free. Take a look, you might find it useful here and there.