I bought a 1200 watt Pure Sine Wave inverter on eBay. More info here:
http://classbforum.com/phpBB2/viewtopic.php?t=779
Photos of the installation are here:
http://classbforum.com/phpBB2/viewtopic.php?p=2459
The job was relatively easy because I'm powering the inverter from battery switch that I had installed previously:
I can choose from (1) battery bank 1, (2) battery bank 2, (3) both combined, or (4) Off, with the battery selector switch.