Wifi Signal Strength App?

I downloaded an app, WiFinder, several years ago that would allow me to specify what wifi to tie into with my iPod Touch. What I liked about it was that it gave me the signal strength so when I was a a public restaurant I could sit in the area with the strongest or at least stronger signal. But with a new version of the OS it stopped working and now when I click on it it just doesn't activate. What I am wondering is if there is another app that would give me the signal strenght for a wifi hot spot? Anyone know? I would think there is a need for such an app if none exists. Thanks.