There are a lot of different techniques, but I'll tell you what I do.  I usually turn out 2-3 "strike" dogs to find and bay the hogs, and then I lead my catch dog in with me until I get close to the bay.  I prefer to be able to see the hog but that doesn't always happen, so when I know I'm close I'll turn the "catch" dog loose and he'll go in and catch the hog, usually by the ear.  Once he has the hog caught, it's my job to follow him and grab the hog by the back legs and flip him to his side.  from there the hog can be either killed with a knife of tied and taken out live. 

Cur breeds are pretty commonly used for hogs as strike dogs, like Blackmouth Curs and Catahoulas.  Jagdterriers and hounds are used too.  For catch dogs, Pits, American Bulldogs, and Argentine Dogos are probably the most common.  All my strike dogs except one have at least 1/4 catahoula in them, and the one that doesn't is a 1/2 bluetick 1/2 heeler oddball freak that happened to work out.  For catching I've got a little Pit, and a young American bulldog that is just getting started. 

As far as I'm concerned dogs are by far the most fun way to hunt hogs.  I get many times the adrenaline rush from unclipping a catch dog's lead than I do from pulling a rifle trigger.  I'll always be a bowhunter, but for me dogs are the way to go. 

What I've written is a pretty simple, Reader's Digest sort of explanation.  The one thing about doggin that is absolute is that there are no absolutes.  Lots of different breeds, crosses, and different methods of using them out there.  If you have more questions please ask, I'll do my best to answer