The OTA looks to be rolling out in two parts. A small 1.6MB download to prep the device followed by the full 364.54MB Jelly Bean OTA update. Which also brings in HTC Sense 4+, like on the One X+ and various other wonders.  If your country is listed and your CID number is one of the mentioned two for the time being, then you can ping HTC through your devices Settings>About>Software Updates> Check Now. No promises or guarantees of course.
I wonder how long it will take AT&T to get the update out to their One X users? It was mentioned in the HTC One X+ press release that Jelly Bean for the One S and One X was on its way sometime in October. Now that it is really starting to get some momentum, hopefully it won’t take too long.
Source: HTCSource