Safe to say is that you are visiting this site because you have an interest in photography - and most likely a strong interest in Canon or Nikon cameras and lenses. Both of these brands call Japan home, and we all know the tragic devastation being experienced by this country.
Canon and Nikon have both issued general statements indicating that they are experiencing production disruption. Canon has had damage to their Utsunomiya factory - We know that Canon's lenses are made in this plant (the U in the Canon date code represents Utsunomiya, Japan). We also know that Nikon's pro DSLR plant is located in the hard-hit city of Sendai, Japan.
Even if building repairs are able to be made quickly, electricity supply remains in question (rolling blackouts are currently occurring). Transportation is an issue. Raw material and parts supplies may or may not be impacted.
Neither Nikon or Canon (I've asked) are making predictions on forthcoming supply constraints, and they probably do not yet have a full understanding of what the future holds.
I fully expect both of these companies to return to 100% production at some time in the future - either at the current locations or alternative locations. But the bottom line is that, due to the disruption caused by the earthquake and tsunami in Japan, I'm concerned about the short-term availability of some Canon and Nikon DSLRs and lenses.
Without knowing Canon and Nikon's inventory levels throughout the supply chain, my advice is: If you know you want or are going to need a camera or lens in the next months (3, 6, 9?), I suggest that you buy it now to insure you have it when you need or want it.
Of course, the concern over camera and lens supply pales in comparison with the concern for the people of Japan. I think I speak for all of us when I say "Japan, stay strong - our prayers are with you."