Scripting in Vegas allows you to extend the power of the program and eliminate many repetitive tasks. For example, suppose you add 100 pictures to the timeline. My first step would be to go into Pan/Crop for EACH of those pictures, right-click the image, and then choose "Match Output Aspect". Now they can all be done in a split second using the "Matchaspect.js" script.

At the far other end of the spectrum you will find Excalibur, Neon, and Tsunami which not only simplifies some tasks but also adds entirely new functions. For example, Excalibur adds an entirely new Multi-Cam editing function to Vegas including the abilitiy to sync multiple clips.

As for the API, the best way to learn is probably to look at some existing scripts. Coming from a VB background, there aren't many examples. You can find a few at http://midihead.servehttp.com/. However, MOST of the scripts you will find are written in JScript and there HAS been some compatibility problems related to using VB scripts. So, I would recommend using JScript instead - it's similar enough to VB that it shouldn't take long to get to speed (I started with a VB background).

If you are unsure what scripting can do, just download the demos of Excalibur, Neon, or Tsunami. Also look at the other freely available scripts at any of the various places they are available.

Tsunami - A Wave of Editing Tools for Vegas

Excalibur - Slicing through your editing tasks and Neon

Batch Render Pro and other scripts

Sundance Media Group

Vegas Scripts at Ayizwe.net

Creative Cow Scripts

Midihead Scripts (Lars Netzel)

Vegas Tips, Tricks, and Scripts Newsletter

Scripting FAQ and API