Here in Tokyo, all the infrastructure is fine "so far". I say "so far" because you never know when the power will be cut. As you may know, Nuclear Power Plants in Fukushima which is about 250km/150miles north east of Tokyo are almost out of control. Therefore, power supply is drastically low and scheduled power outages by region are conducted from today. While the central Tokyo is not affected today, you never know when we will be included. Because of the power shortage, many companies/services are limited. Train services are severely limited and are trying to save electricity. Other businesses are also voluntarily saving electricity. Rollover power outages may cause a lot of disruptions.

The explosion of nuclear power plants is still on the table. We have been earthquakes still here in Tokyo every hour or so.

In conclusion, I think it's better not to come to Tokyo right now until things are getting calm. You don't want to be stranded and miss your flight back to your city from Tokyo, you know. This is something we have never experienced in history so there are a lot of uncertain things including whether traffic signals will work fine during power outages and etc. (maybe not) so if you can cancel your trip to Tokyo, you should and go to Kyoto or Osaka.