Connected cars are a rapidly expanding market in the US as more and more consumers utilize internet-connected and cloud-based services for things like music and navigation. While this is far from the first LTE-connected car announcement, AT&T's is probably the broadest-reaching to date, with the nation's 2nd largest wireless provider promising Mobile Share data integration with over 30 GM vehicles by the end of 2014.
By GM, that of course means the brand's major subsidiaries - Chevrolet, Buick, GMC, and Cadillac. The first GM vehicle to support this LTE connectivity will be the 2015 Impala (the 2014 is still on Chevy's site, but 2015's brings no major changes) which, if you ask me, is actually drop-dead gorgeous for an American sedan (the car received a major makeover for the 2014 model year).
Throughout the year, GM's new 2015 models will probably almost universally be equipped with this functionality, though it seems like previous model years will be left out for somewhat obvious reasons (probably lacking the necessary hardware). The full list is available on GM's website.
So, aside from the $10 you have to fork over to AT&T, is there a catch? We're talking about car manufacturers and optional extras, so of course there's a catch. The catch in this case is GM's widely-flogged OnStar service, which you must subscribe to if you want that sweet LTE goodness. What isn't made concrete is which plans will support AT&T's LTE connectivity through the Mobile Share fee. Non-premium OnStar subscribers (OnStar Basic) will be able to purchase data without going through AT&T, though at a higher price than premium subscribers or through AT&T's Mobile Share plans. It's not made clear if AT&T subscribers wishing to use the $10 / month Mobile Share add-on would need to be OnStar premium subscribers, which would mean at least the entry-level OnStar plan,which itself costs $20 a month or $200 a year. Most consumers typically buy these options as part of their vehicle financing, though, so the cost is spread out over the lease or financing term, lessening the sting. It's also possible OnStar Basic (free for 5 years on most GM vehicles) will support the Mobile Share option, though, which would mean no additional fees to fork over to the General.
For more info, you can head to GM's press release.