ciao scarica questa classe php
Snoopy
ecco un esempio di come poterla utilòizzare.
Certo fa piu di quello che ti serve, ma è veloce e ti permette di estrarre i testi da una pagina html, per poi poter effettuare la ricerca 
codice:
CLASS METHODS:
fetch($URI)
-----------
This is the method used for fetching the contents of a web page.
$URI is the fully qualified URL of the page to fetch.
The results of the fetch are stored in $this->results.
If you are fetching frames, then $this->results
contains each frame fetched in an array.
fetchtext($URI)
---------------
This behaves exactly like fetch() except that it only returns
the text from the page, stripping out html tags and other
irrelevant data.
fetchform($URI)
---------------
This behaves exactly like fetch() except that it only returns
the form elements from the page, stripping out html tags and other
irrelevant data.
fetchlinks($URI)
----------------
This behaves exactly like fetch() except that it only returns
the links from the page. By default, relative links are
converted to their fully qualified URL form.
submit($URI,$formvars)
----------------------
This submits a form to the specified $URI. $formvars is an
array of the form variables to pass.
submittext($URI,$formvars)
--------------------------
This behaves exactly like submit() except that it only returns
the text from the page, stripping out html tags and other
irrelevant data.
submitlinks($URI)
----------------
This behaves exactly like submit() except that it only returns
the links from the page. By default, relative links are
converted to their fully qualified URL form.