Application Notes

Application notes are a great source of useful information on how to design whole systems. They are probably one of the first places to look when designing a new piece of hardware. Here is a quick list of energy monitor/meter application notes that look useful:

AVR465: Single-Phase Power/Energy Meter with Tamper Detection

Current measurement done with CT sensors. Voltage measurement is direct. Interesting use of switchable gain amplifiers to increase accuracy at smaller currents.

Special function Energy meter/monitoring IC's

As well as the IC's themselves there's quite a bit of info here about how to connect up CT's and voltage measurement.

SINGLE-PHASE ENERGY MEASUREMENT IC WITH 8052 MCU, RTC, AND LCD DRIVER (Thanks to Hendrik for the link)

Analog Devices Technical Documentation page (wish I'd looked for this earlier, looks full of useful info)

AN-758: Creating a Reactive Energy Pulse Output Based on the ADE7753

AN-564: A Power Meter Reference Design Based on the ADE7756

ADE7753 Evaluation Board Documentation

A 3-Phase Power Meter Based on the ADE7752 Application Note (AN-641)

Microchip: IEC Compliant Active-Energy Meter Design Using the MCP3905A/6A

Microchip: PIC18F2520 MCP3909 3-Phase Energy Meter Reference Design

Maxim: Using the MAXQ3180 Analog Front-End in a Single-Phase Configuration

Other useful info