How do I get these toggles in my notification bar? I was reading an article talking about the Galaxy Nexus vs. the Galaxy SIII, and ended up buying a Nexus (was a steal, and I knew it was getting JB).

Anyway, I've recently updated it to Jellybean, but I realised that I didn't have something that was showing in the article - the toggles they showed in the Notification bar (in the right hand image).

Are these provided in the standard ROM, by an app, or in a custom ROM? I can't seem to find them.
These toggles aren't part of Android. Third party ROMs like CyanogenMod and MIUI, and certain skins that Hardware manufacturers put on Android include that.

If you want to have this functionality on a Nexus running stock Android you might want to try these two applications, I have used them both, and they are quite stable and useful.

Power Toggles : 
https://play.google.com/store/apps/details?id=com.painless.pc

More Quickly Panel: 
https://play.google.com/store/apps/details?id=com.mabware.android.MoreQuicklyPanel