After seeing this calendar of summer movie openings in the NY Times this weekend, I put all the movies that I was interested in seeing into a calendar in iCal. If someone wants to go through the rest of the list and add them to the calendar, I would be happy to host and/or link to the finished file.
Update: I corrected the link to the iCal file. Typos again! Argh!!!
Update #2: Relatedly, Apple has a movie releases calendar that you can subscribe to that goes about a month out. Bit weird that each movie isn't a separate item, but still useful. Thx, Tim.