Xbox Video to VGA PC Video Adapter Kit 

Ingredients- (kit here)
1 Xbox Video Cord
1 15pin Sub Mini HD Socket
1 sound cord 1/8 mini
D sub shield
Pins
SOG Sync On Green Monitor.  List of Compatible Monitors
Bios capable of handling VGA output

Tools-
Crimper
Soldering Iron
Mini Screwdriver

Wiring Diagram- http://xbox-linux.sourceforge.net/docs/howtovga.html

I tried this once using soldier cup VGA connectors it worked alright but the crimp type is definitely a step up in ease of assembly.  Once I get some photos I will post them.  The process goes something like, clip the connector end from the Xbox SCART cable and clip the RCA connector ends off.  Then remove the plastic cover from the Xbox end, de-soldier the wires, re-solder, crimp pins or sockets on the opposite end and assemble into either the male or female VGA connector.  Choose the end that works best for you, the male end can connect directly into the back of a monitor, the female end can connect into a monitor's VGA cable.  Some monitors have the cable permanently attached to the monitor so female end would be the only choice for those.  I also got some mini audio extension cables so you can use the male or female end to wire into the connect for easy connection to PC speakers, use female to connect to a separate set of speakers or male and use line in on an existing sound card on another computer.