The promise of cloud computing has been around for years.

Like any new technology, it's taken time for the vendor community to work out the kinks and get cloud computing ready for prime time.

While cloud computing comes in numerous flavors, what I'm going to address and what's typically most relevant to small or mid-sized businesses is software-as-a-service (SaaS). This means that applications are hosted by service providers instead of running on your hardware in the office.

This is a big deal.

My company -- a global PR firm with offices across the United States, Asia, and Europe -- depends on extremely high service levels from the IT function. As a one-woman band managing our technology operation, I'm always striving to simplify IT deployment, but it can't be done at the expense of functionality.

This is what led me to evaluate cloud computing for our office applications. After doing my homework, three options were left on the table: Microsoft, Google, and Amazon.

We opted to go with Microsoft's Business Productivity Online Suite (BPOS) solution which was best-suited for our size, reach, and 24x7 response requirements. This said, you should take the time to evaluate all three options because each provider offers a little different functionality.

Microsoft BPOS is a fully deployed, cloud-based version of Exchange, SharePoint, Office Communications Online, and Office Live Meeting, which allows us to offload basic functions such as e-mail and Web-based collaboration tools.

Why was this important? 

For one, our e-mail servers were almost four-years-old -- ancient in "hardware years." The money saved by not purchasing three new servers was a "no brainer."

Furthermore, this approach meant substantial time savings for our IT department -- i.e., that would be me. Microsoft now handles all updates and maintenance, and we no longer have to pay for applications to screen our e-mail for spam or check e-mail for viruses. 

For context, consider that our users send and receive over 100,000 e-mails a month. Before moving to the cloud, it used to take on average 12 hours just to back-up our systems. Plus we used to spend $3,000 per year on Trend Micro's spam filtering services.  

Rounding out the picture, we were shelling out a chunk of change for collaboration tools such as eRoom (at $300 per license) and Citrix conferencing software ($1,200/per year for just three licenses). 

Microsoft's BPOS enabled us to eliminate these costs and ensure that we always have the most current versions of comparable software and a secure environment. The service also comes with 24x7 technical support including support for multiple languages.

This last point carried some weight in our evaluation process. With Microsoft BPOS, our overseas offices now have quicker response time to e-mail and receive support in their local languages.

I also can't emphasize enough the value of engaging with a knowledgeable third-party IT consultant to assist with the transition to the cloud. Just the task of importing e-mails from the legacy system into the cloud application is not for the squeamish. You want to make sure you have someone at your side who has been through this exercise before.

In our case, we partnered with firm called Zag Technical Services. Zag is a Microsoft Gold Partner, and their consultants helped us wade through all of the costs and steps involved in a successful transition, including the migration of 45 gigabytes of e-mail (which is why I used the term "not for the squeamish.")

As you would expect, our transition to the cloud did not come without its challenges. For example, even though our transition was completed six months ago, I'm still receiving feedback -- prefer that word to "complaints" -- about e-mail limitations. Employees who have been with the company for five, 10, 15 or more years used to have no limitations when it came to e-mail use. Now, all of a sudden they're confined by such parameters as a 15MB limit to attachments and 2GB of storage space.

And it's worth pointing out that moving to the cloud has also meant that I had to relinquish some control. Simple requests to modify backend applications now have to go through Microsoft.

Not a problem going through a service provider if the changes are made fairly instantaneously with a three-, six-, even a 12-hour turnaround. But we are currently looking at three days -- a bit frustrating for an IT director who is used to doing everything herself in-house. 

Nevertheless, from my perspective as well as from our CFO's, the benefits far outweigh any downside.

Our mantra for 2010 is "shaking up the status quo."

Our move to the cloud has IT leading the charge.

Linda Wilson is the IT director of The Hoffman Agency, a global public relations firm with 120 employees.