AT&T's annual developer conference kicked off today in Las Vegas with a series of executive keynotes that focused on its budding LTE network. The company announced a number of new LTE-capable devices, including six Android phones and an LTE-capable Windows Phone 7 device, as well as the Samsung Note and Pantech Element – a waterproof tablet.

Chief marketing officer David Christopher introduced the 2,500 developers in attendance to the company's new developer platform and API catalog. Among the new APIs AT&T is offering developers are tools to integrate apps with AT&T's U-verse set-top boxes.

The company said it expects 10 billion API transactions this year, an exponential increase from the 300 million it saw in 2009.

Perhaps the biggest surprises of the show were appearances by Microsoft CEO Steve Ballmer and Nokia CEO Stephen Elop. The two execs were on hand to talk Windows Phone 7. Elop said that Nokia has chosen AT&T as its primary partner in the company's effort to re-enter the North American market.

Elop said that Windows Phone 7 and Nokia's global brand offer developers a "gateway to the world." While Elop didn't unveil any new devices at the event, he did say that the company will be offering more details on an AT&T-exclusive LTE-capable WP7 phone at a press conference later today.

Ballmer repeated his clarion call of "developers, developers, developers" while pitching WP7 as a natural extension of the company's popular desktop operating system. He said that there are currently 500 million PCs running Windows 7, all of which will be upgradable to Windows 8, which shares many aspects of WP7.

Peter Chou, CEO of HTC, was on hand to announce the HTC Titan II, an LTE-capable WP7 device that Chou said includes a 16-megapixel camera. No details were available on pricing or availability.

AT&T is making a major move to get LTE-capable devices in more hands with a couple of low-priced Android smartphones announced today. The Pantech Burst and the Samsung Exhilarate, both LTE-capable phones, both will sell for $50 on a two-year contract. AT&T also will be offering a package deal for the Pantech Burst smartphone and Pantech Element 8-inch tablet. The two can be had for $250 with two-year contracts on each.

The company also announced the Samsung Skyrocket II HD, Sony Xperia ion and the Samsung Note. The Skyrocket and Xperia ion are both high-end LTE-capable Android smartphones. The previously announced Samsung Note, a hybrid tablet/smartphone that comes with a digital stylus, is being launched exclusively with AT&T.

Along with new smartphone designs, the company also showed off the Sony Vita, a connected portable gaming unit that will seamlessly interact with console gaming systems. AT&T will provide two data plans for the Vita, a 250 MB plan for $14.99 per month, and a 2 GB plan for $25 per month.

AT&T's message to developers pointed directly to its LTE network as the fuel that will power the robust applications and services of the future. The company placed an emphasis on more HTML5 apps to reduce fragmentation, as well as cloud-hosted developer services and storage, all of which will be facilitated by faster network speeds.

AT&T has met its goal of covering 70 million points of presence (POP) by the end of 2011. Ralph de la Vega, president and CEO of AT&T Mobility and Consumer Markets, said the company is on track to complete its LTE rollout by the end of 2013.

Sprint debuts LTE devices ahead of network launch
Sprint's LTE network hasn't launched yet, but that didn't stop the operator from coming out with the first three devices for the service at 2012 International CES in Las Vegas yesterday.

The initial device trifecta comprises the Samsung Galaxy Nexus, LG Viper and a mobile hotspot from Sierra Wireless that's compatible with both Sprint's CDMA and LTE networks and Clearwire's WiMAX service. In total, Sprint plans to launch 15 LTE devices this year, including tablets and USB dongles.

Sprint isn't saying when the gadgets will hit shelves and hasn't provided details about pricing.

Verizon rolls out new LTE devices
At last year's CES, Verizon Wireless held a press conference to announce 10 forthcoming LTE devices. This year, there's no formal on-the-record press party, but the carrier looks to be doing more of the same, rolling out several new LTE devices.

The Droid family, for one, is getting bigger. In coming weeks, the Droid Razr will be available in purple, and the Droid Razr Maxx will hit Planet Earth. The purple Razr will sell for $199.99 with a new two-year agreement, and the Maxx will go for $299.99 with a new two-year contract.

Motorola and Verizon claim the Droid 4 is the thinnest and most powerful LTE qwerty smartphone being offered; it's being shown in both companies' booths. The phone packs a dual-core 1.2 GHz processor and 1 GB of RAM, in addition to a five-row qwerty keyboard with a PC-like layout and edge-lit keys for faster, more precise typing even in the dark.

The Samsung Galaxy Tab 7.7, with support for 3G and 4G, also is headed to Verizon's LTE network in the coming weeks.