There are many offered in script repositories like hotscripts.com, etc.
6:16 am on Jan 22, 2009 (gmt 0)
yeah, there are quite a few, but are they any good? we've come to build our own script a couple of years back (it's perl, it's ugly and I wouldn't recommend to pet it if you value your fingers) because none of the ready ones could do what we wanted (aka a mixture of file-based and http-based indexing, rewriting search urls, supporting boolean queries and the like, handling heavy sites with hundreds of thousands of files). That was how I saw it a couple of years back, things might have changed..