The service will be included with the Premier and Education editions of Google Apps, starting sometime in July. According to the company, Google Apps Connector is designed to ease the transition from internally-hosted tools like Microsoft Exchange to their less expensive Google Apps alternative.
The search giant does have other concerns aside from getting businesses to switch. They also have to worry about service availability. The more a company comes to rely on cloud-based services, the more critical ensuring those services are available around the clock becomes. Google has suffered more than a few public outages in the past year, and while most of them were solved quickly, it's not something that people on the clock want to worry about.