This project was originally published in vol 1 of Make (www.makezine.com) on page 96 and i highly reccomend reading it. Easy to follow wiring diagrams make it the perfect reference to read alongside this version. I've added a couple things you wont find in the mag such as vga over ethernet and alternate tecniques for creating the plugs.
Have fun and as always you can get me at firstname.lastname@example.org
Step 1: Get Parts and Tools
1 Length of Cat5 ethernet cable (complete cable)
1 Length of raw Cat5 cable
2 RJ45 to DB9 FEMALE (serial) converters
alternate: 2 RJ45 to DB9 male AND 2 DB9 female
2 RJ45 to HD15 MALE (monitor) converters
alternate: 2 RJ45 to DB9 male AND 2 HD15 male
1 RJ45 couple
4 RJ45 plugs
1 F-F HD15 gender changer (changes male to female)
Soldering iron and supplies
RJ45 crimping tool
If you have no use for a male to male vga cable you can replace one of the male HD15 connectors with a female and you wont need to buy the gender changer.