Oracle plans to spend about $1 billion to buy software company Art Technology Group.

The acquisition, announced today, will be a cash deal for $6 per share of Cambridge, Mass.-based ATG and is expected to close by early 2011, pending shareholder and regulatory approval.

Oracle said that it sees ATG's e-commerce software as complementary to its own array of CRM (customer relationship management), ERP (enterprise resource planning), retail, and supply chain applications, and that ATG also offers on-demand commerce optimization applications that would help provide a seamless online retail experience.

"More than 1,000 global enterprises rely on ATG's solutions to help increase the value of their online customer interactions," Bob Burke, president and CEO of ATG, said in a statement. "This combination will enhance the ability to bring all their commerce activities together--creating a more consistent and relevant experience for their customers across all interaction channels, including online, in stores, via mobile devices and with call centers."