I can't find out the way I used to do it, so what I did find is if I turn off "Quantize to Frames" that I can have full control. Just need to remember to turn it back on after this project.
As David said, be very careful with this tool as it's very easy to mess things up big time if you're not careful.
If you need it, disable it, do your changes and enable it immediately.
Here's what happened to one user on the Sony Vegas forum. Having that Off by mistake caused me much grief.
Really bad outcomes with mixed progressive and interlaced footage.
The "P" ended up a juddery mess, half my cuts blinked and even the interlaced footage in parts was a bit juddery.
Not so obvious on the LCD monitors while editing but once burned to DVD and played back on a CRT TV, yuck.
If anyone does find the short cut to move a video a half a frame, let me know. Does the new Vegas have this option?
I would use it a lot, because video from my canon and panasonic is always a half a frame off.
Video is meant to be cut/trimmed/moved in whole frame increments, never a partial frame.
You can use the Quantize to Frames option to do this but, for the reasons I outlined above, it's NOT recommended as you WILL (not can, WILL) mess things up.
If the video from your two cameras is, as you say, always half a frame off, then you need to find out why and fix the problem.