FTP Index is a search engine for FTP-Servers. It scans servers for definable filetypes and stores the results in a MySQL-Database. It utilizes the ftpls tool from the ftpcopy package by Uwe Ohse for indexing the servers. It scans multiple servers at the same time by running with multiple processes.

Download: ftpindex.tgz

Have a look at Fast File Search for a similar tool.