Does anyone know an iPhone app that replicates the 'Find My iPhone' feature of MobileMe?

Does anyone know an iPhone app that replicates the 'Find My iPhone' feature of MobileMe?

I'm trying to replicate many of the MobileMe functions using free alternatives, like Google Sync for Contact/Calendar/Email. Storage is being handled by Dropbox as a replacement to iDisk and allows me to delete my important data should it get stolen.