I found a tutorial on how to create a waving flag here:

http://www.vectordiary.com/illustrator/waving-flag-of-the-usa-tutorial/

But that tutorial describes how to do it in illustrator.

I was wondering if someone could tell me how to do something similar in Inkscape. I would image the same functionality exists, but I am not sure where to locate features like extrude & bevel a path or to then apply that shape to give the rectangle a wavy look.

Thank you.

Welcome to InkscapeForum!

It would probably take me a couple of hours to write a tutorial for that specific, or even just general type of image. Unfortunately I just don't have time right now. But luck may be on your side. We have several members here who don't seem to mind writing customized tutorials for individual Inkscape users. You may not get a detailed, all inclusive tutorial, but I suspect someone may want to at least give you some generalized tips.

While Inkscape certainly can create the same image, it may not have the same tools suggested in that tut, for Illustrator. Also, it may very much depend on which flag you want to make, as to exactly how to make it. With the US flag, the stripes will be fairly easy. I think the stars will be the tricky part. But if it's some other flag, it would be hard to say exactly how you might want to approach it.

Anyway, welcome, and good luck

You can do similar with the pattern along path extension.
But that's not how a flag waves.

Here is a great tutorial, how to wave a flag in blender:
http://www.youtube.com/watch?v=ZQDIJ7qmfac

I used LPE, pattern along path, like Lazur mentioned, it came out ok, not great, and I really need to do more work on mine.
It appears to me that the extrapolate in other programs isn't the same as in Inkscape.
good luck, hope yours comes out better than mine!
And, welcome to the Inkscape forum. lots of good people and good info here.
dee

you could use a filter too

open the svg. Go to filter/filter editor