Gizmo5 (owned by SIPphone in San Diego, CA) does all of this and so much more.  Not only can you make free internet calls from your home pc or mobile phone, but it integrates ALL of your instant messaging programs into one while letting you do it, supporting Gizmo5, MSN, AIM, Yahoo! and Jabber…for free.  Other supported features include video calls, file sharing and two-way text messaging, allowing you to send SMS messages directly from your Gizmo5 account.

As an iPhone 3G user, I get pretty decent cellular coverage in the Portland, OR metropolitan area, but it’s not always reasonable to use the ATT network for my calls…especially long ones (both inside the US and outside the US).  Gizmo5 answers this need perfectly.

I opt to use Fring as my iPhone VoIP software on the iPhone when connected to a WiFi network.  Fring allows me to leverage multiple platforms beyond what even Gizmo5 lets me have access to in terms of on-the-go voice.  So if I wanted to, I could make calls over Wifi with the iPhone to Gizmo5 users (similar to the other companies), or I can tap “SIP” after dialing a number to reach an outside line.  Call quality is crystal clear and I haven’t had a dropped call once.

Did I mention how much I’m saving at home talking on Gizmo5 SIP over the ATT minutes in my plan?  I’m seriously considering dropping the level of plan that I have just because of this.

It’s rare to see a company that’s encompassed so many needs in one single application.  Big thanks to SIPphone for giving us one application for an incredibly low overhead to accomplish mobile business in today’s mobile world.