AT&T (News - Alert) has introduced a cloud-based computing service called "AT&T Synaptic Compute as a Service." AT&T will introduce the service in the fourth quarter of 2009 in the U.S. market. AT&T plans to add the service to select global IDCs to meet customer demand internationally.

Using technology from VMware and Sun Microsystems (News - Alert), AT&T’s Synaptic Compute as a Service provides companies with self-service, on-demand access to computing resources, along with management of the network, server, hardware and storage, AT&T says.

The service features a Web portal to order, provision and manage server capacity, or to program the application program interfaces. Customers can be billed monthly or pay by credit card.

Around-the-clock monitoring of the service, as well as service level agreements are available along with no upfront fees, no long-term obligations and no termination fees.

T&T will introduce the service for the U.S. market in the fourth quarter of 2009.

Separately, Verizon Business (News - Alert) earlier in 2009 unveiled its own cloud computing service, dubbed "Computing as a Service," and aimed at both large and mid-sized enterprises.

Verizon’s CaaS allows customers to pay for data-center resources such as storage and application hosting dynamically based on the amount of resources they consume. Verizon also uses VMWare virtualization technology.

Verizon’s offering is giving customers a choice between virtual infrastructure (for example, server resources that are distributed among multiple physical servers) and traditional physical infrastructure. Because while virtual servers might make sense for Web content and applications, for example, apps with high input and output such as databases and email are best supported with dedicated devices.

Enterprises are likely to want such a mix of physical and virtual machines for the foreseeable future, most observers likely agree.