The company, which has just moved to new offices in Kings Cross, London, says it wants greater flexibility and better opportunities for collaboration for journalists.
Most of the package was rolled out in 2008, and Google Mail is being rolled out now.
Andy Beale, technology director, said the new technology platform would improve working practices at the company.
"We had some poor working practices, where teams would attach documents to e-mails and fire them off to multiple people," he said. "We had the usual problems of clogged up in-boxes, and we wanted a solution for how people work today. They want to be able to share things really easily, and they do not want to have to learn a whole new product."
He added that journalists were often posted all over the world to cover events, but did not have the infrastructure to support them. Most of the work done at the company, he added, is collaborative.
"We are not a global organisation, but we have a lot of individuals in a lot of places covering the news. Plus, a lot of people were cut off recently because of the weather. We want to be less reliant on virtual private network infrastructure."
He said the new package, which includes Google Docs, Google Calendar, Google Sites, Google Video and Google Mail, will pay for itself quite quickly. "Being able to offload commodity services to someone else at a cost effective price makes a lot of sense. We will save money, and we are getting a lot more useful product for significantly less money."
Beale estimates that a third of the IT team's time is currently spent on managing the legacy e-mail filtering system, and this will all be freed up as users get more control over their spam e-mail. In addition, Google will cut down on The Guardian's future costs for storage, server and application maintenance.
The next challenge for Beale is migrating over to Google Mail, which he says involves deciding whether to move all existing mail over or start afresh.
He said there were a few legal and security concerns about the system at the beginning of the project. "There were some legal and security concerns at the early stage," he said. "The concerns were around moving to a software as a service model for something so important, because it is effectively our corporate data. But even that was relatively easily dealt with."