AT&T began offering enterprise data plans for iPhones this week, marking the first time the carrier has pitched its popular consumer device directly to businesses.

According to AT&T, each iPhone enterprise plan will require signing a two-year service agreement that will include an activation fee. All three enterprise plans offered by AT&T include unlimited domestic data services, such as Internet and e-mail. The plans offer three different options for Short Message Service, including a plan that allows 200 text messages per month ($45), a 1,500-per-month text plan ($55) and an unlimited text message plan ($65).

Much like the consumer version of the iPhone, the enterprise iPhone offers Internet access through the Safari Web browser and built-in connection capabilities through Wi-Fi, EDGE and Bluetooth 2.0+EDR. The company says that enterprise iPhones will have VPN support, including RSA SecurID, which will provide access to corporate Intranets. The phones will also give users access to corporate e-mail through IMAP or POP3 services, the company says.

While AT&T’s enterprise iPhone offering is sure to generate a lot of interest, the company still has to answer questions about whether the devices are compatible with corporate security infrastructure, as many security experts have warned companies about the potential dangers of allowing iPhones to connect to corporate networks. Last June, for instance, Gartner told IT executives to keep iPhones away from their networks, noting that the device lacks a firewall and does not support e-mail platforms such as Microsoft Exchange or Lotus Notes. Andrew Storms, director of security operations at nCircle Network Security, expressed similar concerns and noted that the devices lacked security management tools needed to manage which devices can and cannot connect to corporate networks.

Others, however, have argued that security concerns about the iPhone are overblown and that consumer devices are constantly encroaching upon corporate networks.

“If you are responsible for keeping data inside of your organization, for the love of everything that is holy, please don't spend too much time on the iPhone,” said David Goldsmith, one of the principals at security consultancy Matasano Securitysaid, in a posting to the Matasano blog last year. “Allow us to remind you about all of the data breaches that are happening thanks to insecure wireless access points, tape backups disappearing, wrapping your newspapers in customers' personal financial information and stolen laptops."