The Google Apps Marketplace launched Tuesday with third-party cloud apps from more than 50 other companies, which will use cloud-based applications to supplement Google's own online applications.

Google is trying to lure enterprise clients over from Microsoft products by making it easy for businesses to quickly add to their Google Apps arsenal.

The program enables integrations with such applications as Google Gmail, Documents, Sites and Calendar.

Once installed to a company's domain, these third-party applications work like native Google applications. With administrator approval, they may interact with calendar, email, document and/or contact data to increase productivity. Administrators can manage the applications from the familiar Google Apps control panel, and employees can open them from within Google Apps, Chris Vander Mey, product manager for the Google Apps Marketplace wrote in a blog post.

With OpenID integration, Google Apps users can access the other applications without signing in separately to each. The Google Apps Marketplace eliminates the worry about software updates, keeping track of different passwords and manual syncing and sharing of data, thereby increasing business productivity and lessening frustrations for users and IT administrators alike. That's the power of the cloud.

According to Mashable, app developers will pay a $100 flat fee and must share 20 percent of their revenue with Google. However, that's lower than the 30 percent required by most other application exchanges, including the Apple App Store.

In comparison, Microsoft has its Pinpoint catalog of Windows Azure applications, but the Google Apps Marketplace aims to be easy, one-stop shopping. Developers can offer their apps for purchase right on Google's site, and clients can buy them there too.