You can submit your site to google webmaster tools but the official google directory is not available. Otherwise there are alot of directories select the best and quality directories submit your site to. It will help you alot in getting some PR juice and it will help you in Search Engine rankings.
Imran, Submit your site to dmoz and wait for approval. Google takes directory data from dmoz. If you are listed in dmoz means you are listed in Google directory.
Just post your website Dmoz directory and wait for approval time, when you get approved dmoz link google takes this link.