First the basics:

Amazon Web Serivces (AWS) - AWS, simply put, is rented, dedicated on-line servers.  Beginning at ten cents per hour, you can rent one or more dedicated servers to run your business.  (Note: at ten cents per hour the cost per month for a server is $72.00)

Google Apps for your Domain (GAFYD) - GAFYD is Googles paid for service for companies.  For $50.00 per user/per year you have access to email, calendaring, word processing, spreadsheets, presentations and more.  I'll discuss security, support, etc. below.

QuickBooks Online (QB Online) - QuickBooks Online is, as it sounds, online accounting.

Software as a Service SaaS Platform as a Service (PaaS) and Software as a Service (SaaS)require their own dedicated blog entry. For now, it will be enough to say that you can create almost any line of business application functionality that you currently use, but on the web. Examples include force.com, PerfectForms and Wolf Frameworks (there are many more.)

All of the above are examples of "Cloud Computing." Actually they are components of a cloud computing solution. With the right planning, guidance and implementation using these and other components you can move your business to the web NOW.