I'd try GotoMeeting tech support, but my guess is "No". The tearing is caused by the video being redrawn by the CPU/GPU in the middle of the monitor refresh. The solution is to compose the entire display off-screen and then flip it on-screen in sync with the monitor (you may have seen this setting in games: vsync). Aero turns on composition to get transparency effects and uses vsync, but this extra off screen copy comes at a performance cost. GotoMeeting turns off composition to get better performance streaming across the network--so they are basically turning off exactly the feature you need to keep videos from tearing. You may get better results with a faster computer or a newer version of GotoMeeting.
they have horrible tech support...they have dismissed this issue...saying "we've never heard of, or experienced this...you can't use aero...good bye"
I've tried this with a monster alienware computer with killer harderware and its the same thing...someone explained that aero is a 3D environment...windows classic/basic is a 2D environment that doesn't handle 3D vsync...we've tried forcing vsync on in the nvidia control panel while in classic and it has no effect....
if this isn't what you mean, can you provide details on how to: "compose the entire display off-screen and then flip it on-screen in sync with the monitor"