You all know Cydia
. You use it every day, or at least every week if you're less app-hungry. Its home to Cycorder, Backgrounder, dTunes, PdaNet, WinterBoard (and hundreds nearing thousands of themes), SBSettings, and more.
We've now got Cydia indexed and searchable online at modmyi.com/cydia
. Of course you can't download anything to your iPhone from there - Cydia has a great searching function built-in,