What are some computer interfacing electric energy meters on the market?
Google Power Meter is one good place to start: AlertMe makes a product for the UK market specifically.

It's also possible to DIY. For 3 phase power, you'd need 3 current transformers, and then something to interface them to (an arduino may fit the bill). Note, be sure you actually have 3-phase: most residential buildings use split-phase (in which case you only need 2 transformers). On top of the hardware, you'd have to write all the software for logging and viewing the data, or interface into the Google Powermeter API.

There's several projects to look at as well:


DIY Interent-connected whole house power monitor
Not so tiny power meter
Arduino Kilowatt meter