One new piece of mobile VoIP software that recent caught my eye was RingFree. RingFree is a mobile VoIP application for the Apple iPhone that leverages a users existing VoIP service provider and the WiFi capabilities of the phone to send and receive VoIP calls.

About RingFree

Based out of San Francisco, the companies first product, which is called the RF Dialer, is the first and only iPhone application that allows SIP URI calls, calls to Voice over IM Services (such as Google Talk, MSN Messenger and Yahoo! Messenger), and other IP-based voice services. RingFree essentially works like a call through service. The first leg of your call goes to a local area number (RingFree server), where the call is then sent via RingFree via the internet to the end recipient.

For the purposes of this review, I used the RingFree RF Dialer in conjunction with JunctionNetworks, my current service provider of choice.

RingFree Pros

What first struck me about the application was how slick it looked. I am big on “style” when it comes to the applications I use. Not only is the application slick, but it is very easy to use an navigate. Set-up on the RF Dialer was painless and because it does not require an downloading or installation, simply go to http://rf.com on the iPhone’s web browser, sign-in (or sign-up) to your account and you are ready to start calling.

For first time users, all you need in order to set-up the RF Dialer with your SIP service account is your SIP service username, password and proxy url. It is really that easy.

I placed a half dozen calls to a number of different locations. Each calls was about three minutes in length, and I used both my AT&T data connection and my home wifi connection to connect to the internet. In all instances, the calls were remarkably crisp. I was amazed that there was no packet loss or jitter, given the number of “transformations” the call most take in order for it to terminate at it’s end recipient.

RingFree Cons

The only drawbacks to the RingFree RF Dialer would come if I wasn’t familiar with the way the service works. For the average Joe, configuring the RF Dialer, might be a problem and when placing a call, a pop-up appears on the iPhone that states “Call…” followed by the local area number (not the number you actually dialed). This could prove confusing to a less savvy consumer. I also could not get RingFree to pass my caller id, so all of my recipients with caller id saw “unknown.”

In all honesty, these are very minor negatives and shouldn’t be a deterrent to a user trying the service.

RingFree Conclusion

This is an excellent piece of software, that I highly recommend those interested in mobile VoIP take a look at. It is is easy to set-up, use and works with just about every SIP service under the sun…and you don’t have to jailbreak your iPhone to get it to work.