Google Soap API

Google deprecated their soap search api reports O'Reilly Radar. Instead Google is promoting its Ajax Search API. The site reports:

The AJAX Search API is great for web applications and users that want to
bling their blog, but does not provide the flexibility of the SOAP API. I am
surprised that it has not been replaced with a GData API instead. The developer
community has been discussing this and do not seem happy with the change. Discussion on the forums have pointed out that Yahoo! has a REST Search API. Live Search also has a SOAP API available.

The service is stopped by not issueing the keys any longer. However, hours later, a hack appeared at Hackszine which will get you the keys. You can obtain the keys from here, the page will show error but you will receive key in email.