A couple of folks using iCal reported some problems with the Hebcal export option for iCal. Apparently the iCalendar file format is slightly incompatible with the vCalendar format used by Lotus Notes and some other apps.
To address this issue, the website now offers both .vcs (vCalendar) and .ics (iCalendar) files for download. The .ics files now have a string timezone identifier (such as TZID=US/Eastern). I think I’ve got these working for the US, but I don’t yet have them working for international cities.