Playing catch-up to Verizon, AT&T (http://www.att.com) says select smartphone customers will soon be able to connect multiple devices from their smartphone — via Wi-Fi — thanks to the new AT&T Mobile Hotspot application. Bundled with the AT&T Data Pro plan, customers will get 4GB for US$45 per month.

Also on Feb. 13, to bring AT&T’s smartphone tethering plan in line with the AT&T Mobile Hotspot offer, AT&T will automatically add the additional 2GB of monthly data usage to smartphone customers already on a tethering plan at no extra charge. Customers will incur the same $20 monthly fee they’re accustomed to paying, only now they’ll receive an extra 2GB of data each month.

AT&T Mobile Hotspot details include connectivity for multiple wireless devices to AT&T’s mobile broadband network and 2GB of data usage for $20 a month, bundled with AT&T’s Data Pro plan ($25/2GB). Customers will receive a text message from AT&T once the additional 2GB has been auto-added to their plan.

AT&T’s announcement does not mention when the feature will come to the iPhone, saying only that the Hotspot will debut with the launch of the HTC Inspire 4G. The Verizon iPhone, which is available for pre-order to current Verizon customers, on Feb. 3 sports a Personal Hotspot feature. It will let you create a Personal Hotspot and share your data connection via WiFi with up to five other devices, such as laptops or other cell phones. It’s similar to Verizon’s Mifi data cards which let users share their wireless broadband with other people.