Just tested a HDMI to VGA adapter for the RPi with my old CRT 1024x768 monitor. It works great! This was the "HD2V04 HDMI to VGA + 3.5mm Audio Jack Converter Adapter Box" from DealExtreme, at $21.70. The VGA port was a bit tight, so I had to make sure it was properly connected. Also, the monitor did not display anything before a cold restart of the Pi. It comes only with a USB power cable, to it means a wall wart or powered USB hub is required. (It should go without saying that you don't want to power it off the Pi itself).