I love my single-track bike in large part for its nominal maintenance requirements—there're only so many parts that can actually break—but it's still a good idea to know what exactly what I'm ripping apart before I start. Bike Repair from Atomic Softwares is like an anatomy book for bikes.
The $2 Bike Repair App for Android, iPhone, iPod Touch and iPad is seriously comprehensive, covering most of the bicycle maladies that the average rider is likely to encounter—anything from changing tires to replacing rear derailleur pulley wheels. It's also easy to follow—especially for the less mechanically inclined among us. Just select the offending part from a list, and the app guides you through diagnosis and repair, using large pictures and small words to illustrate each step. It also helped me identify and make the necessary ride-height adjustments to alleviate some chronic knee pain I'd been experiencing after longer rides. (BIG PLUS.)
I kept smearing grease and shit all over my phone's screen during repairs because you have to swipe across to advance the page. Also, the Android version lacks the messaging capabilities seen in the iOS edition. [Atomic Softwares]
Video Music courtesy of Kevin MacLeod. Monster Promenade from the album Oddities