I've been on a Voice over IP kick lately. In two recent columns, I showed you how to take advantage of VoIP's benefits--low long-distance rates and unified messaging--without actually signing up for an Internet telephony service.

This week, I'm returning to the VoIP well. Why? Because there are some compelling new ways to use Internet telephony services. Here's a quick look at three.

Wi-Fi Phones

Vonage offers a telephone that lets you make VoIP calls by connecting to a Wi-Fi access point. As long as you're within range (roughly 200 feet or so), you can use the handset to place and receive calls using your Vonage VoIP service.

The Vonage Wi-Fi UTStarcom F1000 phone is compact, so it's easy to travel with. And when traveling, you could reduce your cell phone bill by using the Vonage phone on a hotel or airport wireless network.

In my informal tests, the UTStarcom phone was easy to set up, as long as I was connecting to an unsecured wireless network. Connecting to a network secured with WEP encryption requires entering the encryption key, which is cumbersome. (You can also connect to wireless networks secured with WPA-PSK encryption, though I didn't test that.) Another drawback: You can't use the phone at hotspots requiring a usage fee, such as the T-Mobile access points at Starbucks. The phone was recently available for $80 after an instant $50 rebate.

UTStarcom has also announced a new phone that lets you make cell phone calls as well as VoIP calls over a Wi-Fi connection. The GF200 is expected to be available sometime soon, according to the company.

Skype Speakerphones

A number of speakerphones that work with Skype's popular VoIP service have become available in recent months. One that I tried, Mvox's MV900 ($130), is both a Skype speakerphone, when attached to your PC via a USB cable, and a Bluetooth speakerphone for Bluetooth-enabled cell phones. The MV900 is small and lightweight, and i worked well in my informal tests. Go to the Mvox site for details.

Skype on PDAs and Cell Phones

You're no longer tethered to your PC to make Skype calls. A free utility called Skype for Pocket PC lets you initiate Skype calls on Wi-Fi-enabled Windows Mobile PDAs or smart phones connected to a 3G cellular network. As part of her review of the Pharos Traveler GPS 525, Denny Arar tested Skype's bundled software.

A new product called VoSKY Call Center connects to your PC and lets you make and receive Skype calls on any handset, including your mobile phone. I haven't tested it, but The New York Times had mostly positive things to say.