WatchTV should be available on virtually any modern smartphone or web browser as well as unspecified streaming media hubs.
The plans arrive next week and start at $70 per month for an individual line (after using AutoPay and paperless bill credits) for the regular Unlimited &More plan, which doesn't include any tethering and limits video quality to 480p. It's a hike of $5 more per month over Unlimited Choice Enhanced, although multi-line service starts at $40 per line. You'll need to pay $80 per month (again after credits) for &More Premium to get 15GB of full-speed tethering and 1080p video streaming, but there is a perk beyond that: you can add a premium service of your choice. It can be another TV network (such as HBO, Showtime or Starz) or a streaming music provider like Amazon Music Unlimited or Pandora Premium.
And in case you're wondering: AT&T is still committed to launching WatchTV as a $15 stand-alone service, whether or not you're a subscriber to one of its existing deals. More details are "coming soon."
Like Verizon, AT&T is adding some complexity to its wireless service. There's a different focus here, though. Where Verizon centered on the quality of the core wireless service with its recent addition of a higher-end tier (more high-speed data and travel packages), AT&T is betting that more content will be the draw. That's not necessarily a bad bet when many of its customers are dropping conventional TV. As you may have noticed, though, it's also an opportunity for the company to both raise the effective price for some users and upsell people to its own video offerings instead of competing services like T-Mobile's favorite, Netflix. It might make sense if you're a cord-cutter or don't care for internet originals, but you may want to check your current viewing habits before switching plans.