College kids, hungry journalists, and other cost-conscious consumers like the word free. We looked at three "free-ish" services that use a computer rather than a phone to make calls. We say free-ish because the software is free to download, and with some services, calls to other people using the same service are also free. But calls routed through the PSTN (public switched telephone network), the traditional phone system, are charged on a per-minute or monthly basis. Still, the rates for domestic long-distance and international calls are often below what your local phone company charges.

The products shown here are not a replacement for your regular phone, because they don't have an associated phone number to receive inbound calls from the PSTN. But they do make a nice complement to your existing land-line phone for low-cost long-distance calls.

When you make a call using the software, the voice data is encoded and compressed, sent to the vendor's online service, and routed through either the PSTN or directly to another computer using the same service. When using these services, you'll almost certainly want to purchase a headset with a microphone, to avoid echoes and feedback from speakers and desktop microphones.

So is this legal? The answer is yes—for now. The Federal Communications Commission has recently ruled that Voice over IP will be regulated at the federal, not state, level. If these products are found to be more like instant messengers, such as those from Yahoo!, MSN, and AOL, they probably won't be regulated. If the FCC sees them as phone services, look out.

The next logical question is, how is the voice quality? With all three services we reviewed, call quality was very acceptable over a broadband connection. We tested with both a laptop using Wi-Fi and a desktop using DSL. Although we did not test with a cable modem, we expect your results should be similar. The PSTN is more reliable, but these services will satisfy most people with decent broadband ISP connections.

Trying these services over dial-up, however, is a different story. When we tested with a dial-up modem, the voice quality was akin to a bad cell-phone connection. Though you'll save a significant amount of money, it may not be worth the trade-off to suffer through a conversation listening to static and dropped words.

Also keep in mind that none of these services are interoperable, though some of them are working on this through the use of Session Initiation Protocol (SIP) and compatible codecs.