Nice work. I see IMDB still don't have an API. I wrote a little movie comparison web app in the past and had to resort to screen scraping IMDB too. Rotten Tomatoes on the other hand seems to embrace developers a lot more and has an excellent API.
EDIT: Just realised you aren't actually screen scraping IMDB but using OMDB API (http://www.omdbapi.com) instead, I'll have to check that out.
IMDb do have an API, for eg. app.imdb.com, however this is meant for mobile applications and it can only be used if authorized in writing(!) by IMDb.
On CPAN there is WebService::IMDB module which uses this mobile API. Also there is IMBDB::File but (i believe) this works by web scraping IMDb website.
EDIT: Just realised you aren't actually screen scraping IMDB but using OMDB API (http://www.omdbapi.com) instead, I'll have to check that out.