I found this today and thought it was very well done - a lot of cool techniques and for those of that use Waves plugs...also very helpful.  I'm curious if anyone has ever done anything like this using Sonar as the DAW?  Definitely one of the areas I'm weak in is automation, sidechains, etc... and there's a lot of coolness that can be done here.  Even if there isn't a Sonar equivalent - this is still very well done.
 
http://www.waves.com/yoad...xing-vocals-with-waves

Hi. There are many videos but not sure if it is what you are after.
https://www.youtube.com/results?search_query=mixing+vocals+sonar
 
http://www.cakewalk.com/CakeTV/SONAR-University/Get-Started
 
http://www.cakewalk.com/CakeTV/SONAR-University/Go-Deeper
 
http://www.cakewalk.com/CakeTV/SONAR-University/Master-Class
 
Hope it helps.
All the best.
 
 

As Zargg said, there are many videos on mixing vocals and if you see a video using a particular plugin, you can usually substitute the plugin with one included in Sonar or you can just go out and buy the plugin yourself.
 
I like the Recording Revolution YouTube channel primarily because of the way he explains his actions and methods.  There are several other great video channels out there at well.  Also, as you saw, Waves has nice Webinars and video tutorials as too.
 
Check out the Recording Revolution You Tube videos about Vocals when you get the chance. He  also explains a hist of other recording techniques.