VoIP, Voice over Internet Protocol, is a data-only phone call. That’s great for mobile devices, because it means you can use WiFi (News - Alert) or your smartphone’s data plan to make and receive voice calls without using voice minutes, according to Gotta Be Mobile.

As Gotta Be Mobile says, though, “VoIP is generally only going to be an option for those with a solid data connection.”

There are many options of companies who want your business for mobile VoIP, so Gotta Be Mobile has, as they say, “narrowed it down to the two that stand head and shoulders above the crowd.”

One, unsurprisingly, is Skype (News - Alert), practically synonymous with VoIP. And for a reason: “It’s high-quality, simple to use, and reasonably priced.”

Quality is the general concern for VoIP, but as Gotta Be Mobile notes, if your connection is good, “voice quality on Skype-to-Skype calls is extremely crisp and clear. Skype-to-landlines or Skype-to cellphones is still solid, though not nearly as high-quality as Skype-to-Skype.”

And their customer service has improved, Gotta Be Mobile says, from its legendarily bad reputation.

Talkatone is the other VoIP service they recommend. As they explain it, “the calling that Google (News - Alert) offers in Gmail is VoIP. Talkatone, while not directly associated with Google in any way, uses Gmail VoIP calling to let you make free calls on your iPhone (News - Alert), iPod touch, or iPad. As long as you have a Google Voice account, you can use Talkatone to make free calls.”

So again, the price is reasonable under those circumstances over both WiFi and 3G, and it’s even “as simple as pie” to set up.

One caveat Gotta Be Mobile noted: “Talkatone also has Google Voice texting built into the app, but our testing found it to be clunky, awkward, and not recommended for SMS over the official Google Voice app.” Their testing found call quality to be best on like-to-like calls, and almost as good as Skype’s on other calls. Plans with premium features run about $20 per year, although the Gmail calling that this app is using is only going to be free until New Years’ Eve.

Right now the Talkatone app has iAds that display on the screen (Skype doesn’t).

Among other notable services you may want to check out, they say, are Fring (Drawback: “An odd, puke-colored UI that isn’t helping things. Also its ringtone sounds like a Sesame Street DJ scratching a recording of a phone ringing.”) and Toktumi’s Line2, which has handing-off of calls from WiFi to 3G without dropping the call and free unlimited text messaging. It costs ten bucks a month, exorbitantly pricey by Skype or Talkatone standards, but worth it if you like the handoff feature.

Want to learn more about the latest in communications and technology? Then be sure to attend ITEXPO West 2011, taking place Sept. 13-15, 2011, in Austin, Texas. ITEXPO (News - Alert) offers an educational program to help corporate decision makers select the right IP-based voice, video, fax and unified communications solutions to improve their operations. It's also where service providers learn how to profitably roll out the services their subscribers are clamoring for – and where resellers can learn about new growth opportunities. To register, click here.