Screen locking app?

I have a 1st generation iPhone with a non-working lock/power button. Is there any app that allows me to tap it to lock the screen so I don't have to wait the 1 minute for auto lock?

Try the magic screen lock.

The "ScreenDIY" would be the one. Many interesting and powerful DIY features are over there to customize lock screen, home screen, icon...
Noticed it had been reviewed on imore as editor's choice a couple days ago.

Edit: found it, Screen DIY--Awesomize Your iPhone iPod - Page 2 - iPhone, iPad, iPod Forums at iMore.com