They're common here. I'm assuming maybe a very basic oven wouldn't have a self-clean feature, but just about every oven does that's sold here.
The way it works is simple - you make sure your oven is empty, press the "clean" button, and the oven door locks. Then, over about three hours, the oven heats up to some godawful temp, like 800F or 900F, and essentially burns everything off the entire interior surface of the oven, then cools back down.
Open the door at the end of the cycle, and you'll have a little pile of ash to brush up. That's it.
It doesn't work as well on the glass panel on the front, but if you catch it right when it's done, you can usually wipe or scrape the glass clean.
Also, some ovens have a shorter "steam clean" cycle - you pour a few cups of boiling water in the bottom of the oven, and it locks and heats up a bit hotter than usual, but not super-hot, and it creates steam which is supposed to soften all the gunk and make it easy to wipe out, but it doesn't really work that well for me.
Remember a while ago we were talking about pizza ovens? I made the comment then that a couple of people I know have permanently disabled the safety lock on the oven, and when they want to bake a pizza the "real" way, they'll run a clean cycle, let the oven heat up to that super-hot temp, then throw their pizza in and they can churn them out in 90 seconds or so, just like a wood-fired oven.
I always leave my pizza stone in and it'll burn that clean as well, and it's also a good way to strip the seasoning from a cast iron skillet, if you ever want to re-season one from scratch.
I should say I have an electric oven, not gas. I'm not sure about a gas oven, but I'd think they'd have something similar.