SkypeOut: You can but time as you go, or pay a monthly fee for unlimited calling within your country. I pay $3 a month, or $24 US a year.

SkypeIn: For $60 US a year, I get unlimited incoming calls via Skype. I can take calls at my computer, using a Skype-enabled phone, or even on my Blackberry using a free application called iSkoot (which supports several different phones, not just Blackberries).

So basically I have a fully-functioning phone number with unlimited calling anywhere within the US for $84 US a year. Not too bad! I even have a cheap little handset attached to my computer, so I don’t have to wear a headset all the time in case anyone calls. The handset looks and acts just like a real phone, except it’s plugged into the computer instead of into the wall.

Skype lets me do business in my home office without relying on my mobilephone and without having to put in a second land line. With SkypeIn, I even have a phone number I can put on my business card.

That’s a pretty good deal, I think – but there are a wide range of plugins for Skype that allow it to do much, much more.

The one I use at least once or twice a week is CallGraph. CallGraph is a free plugin that records every call I make or receive via Skype. Normally it runs in the background, but a control panel pops up as soon as Skype becomes active. I use this for recording interviews with sources, as well as the occasional podcast interview. (Note: Be sure to ask your otehr party as soon as possible if they mind if you record the call – in many cases it won’t matter, but in some states – and I assume countries – it’s against the law to record a call without permission even if the person recording it is not in that state.)

Another valuable plugin is called PamFax and, as you can probably guess, it allows you to send faxes via Skype. PamFax is free, but it charges a small amount per page to actually send faxes – fortunately, it iwll use your existing SkypeOut credit if you have any, or you can deposit a small amount directly to PamFax. An online dashboard allows you to review your sent faxes from anywhere. PamFax allows me to send faxes even though there’s no landline in my office – ideal for returning signed contracts to editors and clients.

SKype is an incredibly powerful platform. There are a whole range of plugins for collaboration, for example, that effectively turn Skype into a teleconferencing system. I don’t use any of them, since I rarely collaborate online, but for people making presentations to clients, there are at least a dozen choices. And the Skype developer community seems to be growing – who knows what we’ll see next. If you haven’t gotten set up with Skype yet, make sure to download the application today – even if you don’t use it to replace your landline phone, you can still communicate via voice chat with other Skype users for free.

And it sounds really good.