You know, I don't know either but if I was in your place, I'd call my local propane dealer for a referral or maybe even they could or should do the work.

My googling results suggest I need a licensed gas fitter. Looking up gas fitter in the yellow pages brings me to heating and cooling companies... but surely they wouldn't all do such work? Could a plumber do it?

Possibly a plumber who also works on heating systems.

Argh, preview is my friend.

(Not all plumbers also do heating systems.)

Are these pipes still connected to the gas line?

I've had similar work done by a licensed plumber. My house is riddled with gas pipes in every wall since there was no electricity when the house was built. We had some of the lines removed when we re-did the bathroom and the contractor's plumber did that.

Actually in the past (when I had no money) I've done that work myself, working with gas pipe is actually pretty easy.

If I could resurrect my grandmother's generation, I'd say "pipefitter!" My great-grandfather came to America to do stuff just like that.

Doesn't help you at the moment, though.

Many plumbers are also gas-certified pipefitters.

However, if they're not hooked up to anything, it's something you could do with a Sawz-All and a Saturday afternoon.

if they're not hooked up to anything

Aye, and there's the rub...

pipefitters do still exist in force, or at least did in the Midwest when I was a catering assistant and they had a big annual plumbers/pipefitters union get-together at our big hotel.

I'd do some googling/calling around to see what your local plumbers' / pipefitters' chapter recommends. Keep in mind that a licensed pipefitter is a guild/union member and that often such work may not be cheap. However, as Meatbomb alluded, you need to make sure that these aren't still hooked up to a live line, and paying guild rates is preferable to having Swan's End explode in a firey seething inferno.

also: Sawzalls are Teh Ossom!

At least here, licensing has nothing to do with union membership, it's done through the city. You can't do work in the city legally unless you have a license but no one who's worked on my house has been a union member. Union construction workers almost never do residential work around here, they do government and institutional stuff.

Most plumbers are also gasfitters. I would call a plumber.

I would not try and cut the pipes off yourself unless you are absolutely sure they aren't hooked up to something. I mean, sure to the extent you would stake your life on it, because that is what you would be doing.

I'm pretty sure the one in the back bedroom is hooked up, because it was fairly recently a kitchen. The ones in the attic... probably not, but then I don't really want to take a chance. I'll call plumbing companies and ask specifically about whether they do gas fitting. Thanks everyone!