There are some interesting search engines for you to take a look at. I don't know what you mean by "Google like" so I'm just going to ignore that part.
- Take a look at the Lucene engine. The original is high performance but written in Java. There is a port of Lucene to PHP (already mentioned elsewhere) but it is too slow.
- Take a serious look at the Xapian Project. It's fast. It's written in C++ so you'll most probably have to build it for your target server(s) but has PHP bindings.
