There are dozens of threads about this. I have not bookmarked any of the recent ones, but here are links to two older ones to get you started:

PowerPoint 1

PowerPoint 2

There is no easy method.

You can save each slide as a jpeg or png. Open the presentation In Power Point, go to "Save as" and under the "Save as type" select which file type you want.

Any audio and transitions will have to be added in Vegas.

Then render to whatever format you desire.

Here's another old post:

PowerPoint 3

A lot depends on how you build the powerpoint slide set. When i am building tutorials, I pretty much stick with simple appear / disappear animation effects. I like to put 5 - 7 "appear" transitions on a slide. Getting that ready to output would require that I expand each slide into 5 - 7 with the "appear" transitions mimic'ed by a simple cut or fade to the next slide in vegas. This becomes tedious if one has 30 - 40 slides x 7 to expand them fully.

Fortunately, I found a trick that works pretty good. Set your powerpoint up to work with 4 - 5 seconds between transitions. Then run a slide show. I used a tool called "snagit" for screen capture. Turns out you can set it to auto record at timed intervals. So ... set your power point loose for automagic slide show, and then start "snaggingit" between transitions - and like magic, one now has a complete series of png or whatever files.

Be sure to check thoroughly, as sometimes you might skip a slide or perhaps get one twice

this only works by capturing the state of the powerpoint between transitions. Resolution is pretty good, since I run on 1280x1024 resolution and let vegas squeeze the slides down to SD resolution.