Ask HN: Recommendations for screensharing demos with prospects?

Hi HN, I am trying to set up phone calls where I do demos of my startup to prospective customers. I'd like it to be simple, intuitive, lightweight. - Ideally it's easy for users to type in a URL or go to the site and type in an access code without me sending them something (if possible, but not required). - supports linux (for me) -- gotomeeting was really bad about this initially - Cheap/free is good, but I'm willing to pay for quality - must be web-based -- can not require software downloads - ideally supports a wide range of browsers -- I expect my customer base to be largely using legacy IE versions... I recall seeing something here on HN before that looked really good, but I can't seem to find it now. Any recommendations are appreciated.