can't... , u must buy the plug in... its call MULTICAM...
u can edit up to 4 camera in 4 monitor... like multicamera production... i have its... it so good... ;D
in ppro and i thnink 6.5 too..you can save one track by itself as a project by deleting everything else. then reopen the project with the track you want to compare to .. and switch to the 2 monitor view mode for cutting ,import the project that has the one track you saved as a project, and drag the imported project to the cutting window monitor. you can view them alongside eachother like that , but im not sure if youd be able to do what you want if anything more than view them next to eachother. but you could probably see when to sync them by the remebering the timecode for each track at a point when you can tell they are synced that way. then when you open your original project, you can slide the track which youd saved as a project forward or backwards until the same sync point matches the same point on the other track.. ..so much of a hassle is it possible to use a clapper/slate or somthing to sync by when shooting ?
Here's the best way to do it w/o buying multicam... Sync your two shots. Now one is more or less your secure shot, the "go to" shot that is constantly good. You put this on the bottom of the two. Then you go through and cut out the other camera with more movement so when that camera shot doesnt have a good shot, it goes to your steady shot. Drop in your dissolves and boom. A quick way to edit 2 camera angles.