To get listed in under 24 hours you could try to:
a) Exchange links with a website with a PageRank of 7 or more
b) Purchase text links (don't know if you're keen to spend money)
There are alot of SEO articles out there you should look them up. Some ways are to exchange links with others who have a good Pagerank and also posting on forums and attaching a sig with keywords that can relate back to your website.
getting links from five or six high PR sites may lead to getting indexed within 24 hours.
search engines visit these sites regularly ( almost daily basing on their page rank )
as google or other search engine finds them, it will feel that the site is important to be indexed and it will index soon.
if we get links from low PR sites, it takes a long time to be crawled by SEs.
I have found (at least in the past) that if you put Google Adsense on your site the regular Google Bots are sure to follow in a prompt manner.
Adsense bots and spider bots are two different, unrelated bots.
What the adsense bot does has no effect on the bots that spider for the search engine..
Why not kill 2 birds with one stone, submit to some directories, preferably niche directories targeted at your industry and preferably with a decent PR. This will provide you with back links as well as get you into the search engines quickly at least it's worked for me and other sites I do. Oh yeah and like Basoone pretty much said, don't over do it, just do a few at a time don't do 100 in a week and then stop as Google tracks that.
