Which web service should be used to design a keyword suggestion tool in PHP?

Although many readymade keyword suggestion tools are available these days, I wish to design my own keyword suggestion tool in PHP for practice and learning purpose. Which web services can be useful if I wish to access the Google keyword database? (I'm new to this kind of programming. So, please answer legitimately.)|||If I remember correctly, there is no public access to Google keyword database. You could probably use a packet sniffer to figure out how Google Toolbar in your favorite browser does it...|||Here is some information that may be of help to you:


http://webservices.xml.com/pub/a/ws/2002鈥?/a>





http://www.php.net/soap