The overnight success of iShoot is one of those fantastical stories that causes instant buzz among iPhone developers and fanboys alike. Developer Ethan Nicholas, is having the kind of success with iShoot that many app creators will hope is contagious.

Ethan’s tank combat game originally went live in the App Store back on October 19, 2008. The response from cult of iPhone fanatics was ‘just ok’ according to Nicholas. Soon after its launch, iShoot disappeared into obscurity only after a moderate number of downloads.

“I work a day job at Sun Microsystems,” Nicholas told the iPhone Savior in a short phone interview, “I developed iShoot in my spare time with no updates since it was first released.”

Finding time to tinker with iShoot over the Christmas break, Nicholas decided to release a free “Lite” version of his $2.99 app, hoping it would be rediscovered by iPhone faithful. That brilliant decision turned out to be the magic bullet iShoot needed.

“iShoot Lite” went live on January 3, 2009. Less than ten days later on January 11, the original iShoot rocketed out of obscurity as the number one Top Paid App in the iTunes App Store with 16,972 downloads in one day. It virtually blasted the reigning number one iFart app off its perch overnight. iShoot simultaneously grabbed the Top Free App number one spot as well.

For an app to reach number one and remain there, some 10,000 plus downloads per day are required. That’s roughly $21,000 a day for this $2.99 app after Apple takes its 30-percent stake. Nicholas attributes iShoot’s meteoric rise to the release of his ‘Lite’ version, giving millions a free chance to experience the thrill of launching tank artillery. It’s important to note that a $2.99 price point was no barrier to the ultimate success of iShoot. [over $600K net]

“I’m still in shock,” Nicholas said, “I’ve given my two week notice at Sun Microsystems. I’m gonna do this full time now.”

Nicholas admitted that’s he’s not a seasoned Mac developer. In fact, he had no experience with Objective-C programming prior to creating iShoot. That’s one revelation that makes his epic success story sound even more unreal.

“iShoot was the first app I developed using Objective-C,” Nicholas said, “It was created on an original MacBook that was in rough shape. The Wi-Fi was dead and even the Ethernet port had to be jiggled for it to work right.”