Calling all small businesses
There are unified messaging services created just for small businesses. Features are geared to a small group of employees that may be on the go and need to communicate.

Consider voice recognition
This may seem like a frivolous bonus, but it actually makes a big difference. If you don't have a PC nearby with Web access and get easily annoyed with maneuvering with a phone keypad, the extra dollars may be worth it.

When free is not so "free"
When registering for a free service, find out if your phone number is toll-free. Having to call number local to your office while you're on the go could quickly escalate your bills. And watch for those services that are going to put ads on your faxes.

Use the right email address
Find out if you can use your existing email address when you sign up with a service. If not, you'll have to update your contacts with another email address - or find another way to access your existing address, which kind of defeats the purpose.

When buying software...
Make sure the software you purchase will support multiple users and is compatible with your network software.