Please don't use Skype for business, it wasn't designed for it, doesn't work terribly well and is comparitively expensive
Look for a business class VoIP service that can grow with you and do the clever things that proper VoIP can do - and do make sure that you choose a company that is a member of ITSPA so that your number is protected.
For info, I get asked this question a lot - here's what I say:
What is the difference between Voipfone and Skype?
There are many very important differences between Voipfone and Skype things like call quality, reliability, customer service, price (Skype is surprisingly expensive), services & features and technology - but the simple and critical difference between Voipfone and Skype is that Skype is NOT a telephone company and Voipfone is.
Skype is a software application that runs on your PC, not a telephone service. Skype go out of their way to explain that they are not a telephone company; they do not, for instance, provide a 999 service - in defiance of UK telephone regulation or have a telephone number that you can call for support.
What is VoIP?
VoIP (Voice over Internet Protocol) is a technology that allows you to make telephone calls over the internet (and other data networks). Its the next generation of telecoms technology and over the next few years all of BTs core networks will be converted to it by their 21st Century Network project. All new PBX (switchboard) equipment is already VoIP enabled.
VoIP is a general description of a technology, the specific technology used by VoIP has now been standardised internationally this is called SIP (Session Initiation Protocol).
So what is Skype?
Skype is a form of VoIP.
But Skype use its own technology which is secret and will not interwork with any other system or service. The world of telecommunications relies totally on accepted international standards so that any telephone anywhere in the world can call any other this is not the case with Skype.
Skype is also a peer to peer system - that is, it uses your own PC and all the other PCs with Skype software on it, to carry their calls. Sometimes it even uses your own bandwidth ie your broadband connection to carry traffic for other people over your connection. See Skype Super Node to find out more
http://en.wikipedia.org/wiki/Supernode_(networking)
This makes it extremely cheap for them as they do not need to provide their own network infrastructure. But it also means that it cannot control the quality of your calls. Because your telephone call is a real time application which, unlike other internet uses like email and web browsing, cannot be slowed down, Skype is at the mercy of an ever increasingly congested network which can and does interfere with your call.
Skype is a wonderful application which brought VoIP to everyones attention and the industry would not be what it is today without it, but it was never designed or even envisaged as a business application or even a telephone service - and it isnt.