There's no magic URL to go to, just enter (and bookmark) imdb.com in your Symbian Web browser:
Note the kinetic scrolling thumbnail shortcuts for both movies and actors, it's rather swish to see this in a 'mere' mobile web page; here I've swiped the movie strip to the left, to show the scrolling at work; note also the ever present search box - finding something movie or TV-related is only ever a typed word away.
Tapping through to a title brings up a similar details pane, with shortcuts to many areas showcased below. In addition to watching the trailer (a MP4 download - best to wait til it's finished downloading for best results - and there's the added benefit that you can watch this offline again in the future), you can sign into your IMDB account to add the title to your 'Watchlist' or to 'Check In'.
Scroll down further for typical details of each movie, along with links to IMDB's fabulous content, including critic and user reviews (shown above, right).
The Parents Guide is particularly useful at identifying what bits might offend or scare; also, the wonderful Trivia section.
It's not movies, either, IMDB has loads of information on TV series, as seen here. Everything's here apart from trailers (since this is TV).
Charts are available from the Box Office, though only for the USA, it seems. At any point, you can follow your nose through hyperlinks from title to actor to filmography and then back round again. Warning: entering the world of IMDB could seriously impact your productivity....
Finally, there's integration between the IMDB mobile site and your Symbian phone's Positioning system, so showtimes can be displayed for the cinemas immediately around you, albeit with no way to actually book tickets within the page.
Yes, there's an element of me being peverse in exploring a mobile web route to IMDB, but it's better than ranting about how the developers at the company should be thinking of Symbian - something which, at this stage, may never happen?
Hoping this walkthrough inspires you to check out and bookmark IMDB on your Symbian smartphone, anyway!