Leaving out the joke about whether this app comes with an obnoxious service charge, the Live Nation app is incredibly sound. If you live in an area with a robust concert scene that can be difficult to keep up with, this won't be the only app you'll need, but it's not a bad one to keep around, all the same.
Finding concerts on Live Nation is as simple as can be. Users can either search for an artist or venue or scroll through the listings for either to see what shows are upcoming. The only limit on what you can find venue-wise is limited by the venues that book with Live Nation. That means smaller, indie-friendly venues won't have their shows listed here, but for the larger concert halls in your area, you're well-covered.
In addition to those searches, the Live Nation app also has a nice bit of info on each venue. From address, phone number and directions, to a breakdown of the parking and public-transportation options available, there isn't a stone left unturned. Something like this could be very helpful for an out-of-towner looking to see a show in an unfamiliar city.
The Live Nation app also has two more surprising features that don't necessarily add or subtract from the total package. The first is an inbox that only goes one way. That is, users can't send messages out, but presumably when there are updates to the app, the updates will be listed in this inbox. Perhaps also if one of the artists you've selected as a "favorite" announces a concert date, that notification would go here, though I'm not sure about that.
The other feature is at least music-centric: a set-list listing for an absurd amount of bands. While bands found on the iPod app of your iPhone are all listed in the favorites section, the listing goes so much deeper. It seems strange because it doesn't really have a great correlation with actually purchasing live music, but it's pretty cool nonetheless.
I admit I was surprised to see how much info was packed into this app. The ability to purchase tickets on it, in addition to looking up concert dates, was a tremendous bonus. Although the app tends to crash here and there, for a free concert-centric app, Live Nation is one of the best I've seen in function and form.