did you follow the links? It pretty-much explains it and how to use it...
[man]file_get_contents/man does not just take the base URL as its parameter. You can use dynamic URLs (as my example below illustrates). [man]fopen/man and [man]fread/man can do exactly what file_get_contents does, but in a few more lines.
Example
$fcont = file_get_contents('http://www.google.com/search?hl=en&q=bpatterson&btnG=Google+Search');
$focont = '';
$fp = fopen('http://www.google.com/search?hl=en&q=bpatterson&btnG=Google+Search', "r");
while(!feof($fp))
{
$focont .= fread($fp, 8192);
}
fclose($fp);
If you echo both of those strings ($fcont and $focont) it gives the proper output of a google search.... so they both do work, the possibility is in your PHP setup, and using urls in the file_get_contents with urls...
Read the manual as it gives work arounds too