After further investigation I think I've found the offending change in the imdb html. Though I don't have a "before" sample of imdb html to work with; the first line below matches the regex in the scrapper script, whereas the second doesn't. The new code looks like some kind of tracking script disguised as an image.
UPDATE: If you feel uncomfortable following this procedure you can just upgrade to 0.6.2 which includes the new version of this sccript (no other changes). If you already have this script applied an upgrade is not necessary. A few more details here, and you can download here.
Yeah, IMDb changed their site. You guys need to update your IMDb scripts for Moving Pictures.
Download the attached XML file.
Open your Moving Pictures config screen.
Goto the Movie Importer tab.
Click the Data Sources button (see image below).
Click the plus (+) button to add a new script. (see image below)
In the file selection dialog that pops up, select the IMDb.xml file you just downloaded.
Verify the new version of the script has been loaded. This version is 1.0.10, published Dec. 12th, 2008. (see image below)
Now you have the new script and you should be able to retrieve movie details again. To get Moving Pictures to re-search for all the unmatched items listed in the importer, you either need to restart MediaPortal or restart the Importer. To restart the importer:
Goto the Movie Importer tab.
Click the Matches button if it is not already clicked (next to the previously mentioned Data Sources button).
On the toolbar click the gear.
Click restart importer.
Thank Armand for getting this script fixed so quickly.