What is an IFO file? How can I edit it?

My sister in law sent me an IFO file (video) from her SONY camera. My ultimate goal is to be able to import it into iDVD and include it on a slideshow that I'm making. Is this going to be possible? Can I get some kind of conversion software? I also have another PC laptop that I was able to open the file on but it won't let me export it and/or save it as another file type. It's frustrating...can anyone please help? Thanks!

Jameson