how long does it take till new title will be published on imdb?

Please see the following FAQ. I've quoted the opening paragraph for reference.
http://www.imdb.com/help/show_leaf?wh...
I submitted a new title for inclusion in the database. When will it be added?

Every title submitted to the database has to be approved by our editors, who need to verify that it's eligible for inclusion in the database. Please keep in mind that data in the Internet Movie Database is always subject to change and that we reserve the right to reject, withdraw or delete information at any time. ...

Processing times are here:
http://www.imdb.com/czone/times

Interestingly I submitted a film on the 9th and it was already live when I checked earlier today, which was nice, but times vary. Looking at the link I give, they are getting through the backlog of new titles, so it might only be a week or two.

However, it is worth noting that in production films may be held to a higher standard, to stop them having to chase up and remove films that were added and never released. They will include films by notable creators/actors or that have got a lot of press (if you can get some attention and add that to your submission it'd be a big help), but might be less eager about adding a micro-budgeted indie film. The problem is everything else in between - so it is always worth a try, but if it gets rejected you can always resubmit when the film is done and lining up for a release.