Some people said that they can list their/your website in google under 24 hour. This can be done easily. Index in google means, our website is in google's database. You can find out by searching your domain name at google. If you haven't find any result, that means that the website is not in google index.

You can add your website at google by submitting it at http://www.google.com/addurl.html.

This is Google's actual website submission form. They state that you can use this form to
submit your website to their index of websites and it can take up to 6 weeks for your website to
be placed into their index. So how do you get listed in 24 hour?

You need to search website with high PageRank. Higher pagerank means, that they are visited by google more often. Your website will be listed in google more quickly, if you the high PageRank website links to you.