Google Apps for Business and the search giant's enterprise products are now used by more than 50 percent of Fortune 500 companies. So what does that mean in the Google Apps vs. Microsoft Office 365 cloud wars? Actually, it sounds like a very close battle so far. In fact, both Google and Microsoft now rank among the world's Top 100 Cloud Services Providers, according to Talkin' Cloud research that will debut July 30.

Let's start with Google. During an earnings call yesterday, Senior VP and Chief Business Officer Nikesh Arora said:

"...On the enterprise front, that’s another great revenue stream for Google. It comprises productivity apps like Docs and Gmail as well as our Cloud infrastructure. Now more than half of the Fortune 500 companies use the paid enterprise product from Google, and over 5 million businesses use our productivity apps."

Arora said new customers include include Federal Express, Pearson, Keller Williams Realty and the city of Boston. Plus, he noted that HP is now a Google Apps reseller in small business accounts.

Those are all solid milestones, but Google failed to disclose its cloud for business revenues -- again. Plus, the search company did not mention Google App Engine -- the Windows Azure and Amazon Web Services alternative -- during yesterday's earnings call. 

So how does Google's cloud momentum compare to Microsoft's progress in the cloud market? During Microsoft's earnings call yesterday, CFO Amy Hood said Office 365 now has a $1.5 billion annual run rate plus Azure is now used by more than 50 percent of Fortune 500 companies.

Translation: Microsoft and Google are saying the same exact thing about their Fortune 500 penetration. But which company ultimately is ahead in the cloud revenue race? We'll reveal the answer when the third-annual Top 100 Cloud Services Provider report -- aka the Talkin' Cloud 100 -- debuts July 30.