The UK's first professional voice-over-IP service using the SIP protocol has been released in the UK by Fordyce Ltd.

Going live on 1 July, the service is the first in what is universally expected to be a huge market in the next few years - super-cheap phone calls made over the Internet.

Of course, there are lots of companies already offering voice-over-IP, but the problem has been connecting people on Net phones to normal phones and vice-versa, not to mention the fact that phonecalls in themselves are not sufficient for companies to replace existing telephony systems.

However, the arrival of the first SIP-service is the tip of an almighty iceberg. SIP (Session Initiation Protocol) is a relatively new standard but with enormous potential. Essentially, it allows a direct connection between two individual users connected to the Internet - exactly like instant messaging software does at the moment. However SIP has the flexibility to include not only one-line messages, but also voice, video, files, in fact pretty much anything.

The vision is future communications. You're at your PC, you have a list of your contacts - at the click of a mouse you can send them a message, or a file, call them up on the phone or video conference with other people. If they call you, you get a warning when the phone rings - who it is, what they look like, what the last five emails they sent you were. Microsoft is so keen on it, it installed the SIP protocol into Windows XP and gave the market a much-needed boost.

However, despite increasing excitement in the industry, SIP has been relatively slow in arriving in products. Fordyce is hoping to capitalise on leading the way. Its managing director, Christopher Fordyce, explained the packages on offer. There are three: Basic, Standard and Professional.

For the Basic, you call up Fordyce and they give you a pin number, SIP address, username and password. With this set up (and an appropriate phone) you can then call any other SIP-phone anywhere in the world for free over your broadband connection. The service element comes with the inevitable phonecalls over the normal phone network (PSTN). You can call a landline anywhere in the world for 4p a minute or a mobile for 17p a minute. All incoming calls are sent direct to voicemail.

If you want to receive calls, the Standard service costs £5 a month. The call charges are cheaper but not yet set. You are given an 0870 number which will follow you around wherever you are. For Net-phone-to-Net-phone calls, again they are completely free. Someone calling you from a normal phone if you are abroad will only pay a local UK phone rate and you calling the UK from anywhere in the world will also only pay a UK local call rate. All bills are paid online using credit cards.

The only problem with all this is firewalls. The vast majority of people with broadband are behind firewalls and nearly all firewalls currently do not allow SIP communications. There are some on the market however, and, conveniently, Fordyce resells Intertex equipment that allows this. Typically, it would cost £200, Christopher Fordyce told us.

The Professional package is for businesses and the company is currently running a custom service on it, altered to each company's needs such as number of addresses, users, usage etc etc.

Christopher Fordyce explains that the company has been running a free service since November to entice customers and was surprised to find 60 per cent of them came from abroad - usually ex-pats saving small fortunes by calling the UK from abroad at local rates.

However, he tells us that he sees new customers "everywhere I look". Remote workers in particular, he feels will be the first to sign up to the service since it allows immediate one-to-one connections at negligible prices.

Although big companies are still likely to be a while before they shift their phone systems, small business that do a lot of international business or businessmen who travel around a lot may see the benefits almost immediately.

Plus with every analyst under the sun predicting an inevitable shift toward SIP, and Microsoft creating a ready-made market by introducing it into Windows XP, we can expect a lot more SIP services to appear very soon.