That depends upon the website. Some sites are indexed several times a week and some are not even within a month.
It really all comes down to how many links you have pointing to your site and how often the pages linking to your site are crawled, if you are very active on a few different webmaster forums or any forum that allows you to have a link in your sig then you will get indexed in no time as forums are crawled very often especially if they are very active forums like DP and many other of the bbig webmaster forums.
I needed 7 days for my first website 3 years ago. But after I learned what I have to do to get indexed immediately then it was much faster for my new websites.
If your site has huge links then it will be indexed quickly by google. So it depends upon your relevent links.
My site got indexed in 2 days ...i added a lot of content and only 2 backlinks, now i have 27 backlinks
This happen to me ,I sumbit some sitemaps and Google check this right Also I link building daily ,But a month goed ,Google indexd no pages. I change domain name imediately,Did'nt submit sitemaps,Just bookmarking (digg,dtumble..) a page daily,And google index me a page in 2 days. Now ,a week ago ,google index me more 40 pages. You can follow my action to try. Good Luck!
it has been lightning fast since about xmas time but in the last 2 weeks seems to have almost stopped, and exhibiting other random behaviour like picking up one new site from a blog post in a day and not the other one (next to it) for another week and a half. and random de-indexing of well established pages as well.
Again, indexing depends upon the relevent backlinks and frequent changes you have made in your website.