The Louisville NPR show "Homegrown" did a story on the disappearing bees last year, and
The New York Times has been writing about this increasingly as well. In fact, another just today:
http://www.nytimes.com/2007/04/24/science/24bees.html. Nobody seems to know what the reason is, and it's apparently been happening in other parts of the world as well, which would (at least to me, but what do I know) seem to rule out disease. Theories include increased use of pesticides, genetically-modifed crops, the farily recent and increased use of aerial spraying of mosquitos for west nile virus, or maybe the increased clearing of land for new development, etc. Or maybe some new parasite. But nobody really knows.
There are other means of pollinating plants (and it's not all done by bees), but it's my understanding that bees are the most prolific pollinators and among the most proficient. So it's a freaky notion. I'm hoping the scientists studying the issue are coming up with new pollination methods as well. Otherwise we may all have to learn to live without a fair number of foods we take pretty much for granted or expect to start paying a small fortune for them.