FantasyMonster ($3.99, link) is an app for accessing your Yahoo! Fantasy teams (supports baseball, football, basketball, and hockey) on the iPhone, and the best toward that purpose we’ve seen yet. There are other Yahoo! Fantasy iPhone apps available, including MyFantasyTeams and the official Yahoo apps for Fantasy Baseball and Fantasy Football, but FantasyMonster is the best of the bunch by a long shot in terms of usability and legibility. A free lite version is available as well.

While other fantasy apps are adequate enough to check your weekly scores, they aren’t good for serious editing of your team. Tasks such as complex lineup changes or scanning and picking up free agents is frustrating to the point of being undoable.

But FantasyMonster utilizes drop-down menus and vertical scrolling to make it easier and more comfortable to parse information. While viewing statistics on the iPhone’s 3.5-inch screen can never be as comfortable as a larger desktop screen, FantasyMonster handles the necessary compromises well. In short, it makes editing fantasy teams viable on the iPhone for the first time.

I’ve always liked the drag-and-drop interface of the official Yahoo Fantasy sites, and FantasyMonster uses it too, allowing you to drag and drop players into qualifying starting positions or to the bench. It’s pretty surprising that Yahoo’s official apps lack this feature, but FantasyMonster has it. Drag-and-drop makes lineup changes so much quicker than the html-based checkbox method used in other apps.

Stats are quite legible—the app doesn’t try to squeeze everything onto the iPhone’s small screen at once (a flaw of the Yahoo apps). Instead, FantasyMonster utilizes side scrolling so you can comfortably swipe through and view a player’s complete stats.

News headlines are shown in a scannable list form, and tapping on them reveals the entire article in a drop-down, which you can tap again to collapse. Player news, MLB headlines, injuries, and scores can be viewed in this way. It seems the developer has studied good iPhone design techniques and has implemented them into the app.

Another area where all the other fantasy sports apps failed was with the process of scanning and adding free agents. Any fantasy player knows that free agents and the waiver wire is the most important part of fantasy sports. FantasyMonster, with its readable text and stats, is the first app with a usable interface for scanning, sorting, and adding free-agent players.

There are a few things we wished the app handled better. One particular annoyance is how it displays messages (or doesn’t) with the loss of an Internet connection. In one particular instance while viewing player news, a lost data signal meant an error screen taking over the entire screen. I could no longer read player news, despite the fact the info had already downloaded. Likewise, while trying to log in, the app asked me to reenter my login information, while the real problem was that there was no Internet connection.

Conclusion

FantasyMonster is the most usable app we’ve seen for managing your Yahoo! Fantasy sports teams on the iPhone. It offers solutions for the limitations of the iPhone’s small screen and makes editing your team, parsing lots of stats, and picking up free agents doable for the first time.

FantasyMonster is a $3.99 download in the iTunes App Store.