SlideRocket lets you import presentations from Google or Microsoft PowerPoint or create them right within the program, and then access them from any PC, Mac, or Linux computers. You can add audio and share presentations with your Google Contacts. It also includes analytics for measuring audience engagement.

Cost: free.

To take advantage of the Google Apps Marketplace offerings, you need to sign up for a standard, education or Premier Edition ($50 per user account annually) account. You also need to establish a domain name for your business -- it can be a new one, or you can register an existing domain. With Premier Edition, once you establish your account, you get 25 GB per account of Gmail storage plus 1 GB per user of Google Docs storage and 10 GB plus 500 MB per user of Google Sites storage. And with Premier Edition, your business can download and install apps for everything from planning a project to creating an invoice. They not only work as independent solutions, they often interact with the native Google applications from Google calendar to Gmail and more.

Further reading: 12 Essential Android Apps For SMBs