After reading this I found out that all I needed was a 4.7 Ohm 1/4 Watt fusible resistor, luck was on my side and I found a local supplier which had some for 60 cents.

I didn't have a decent soldering iron so I got a friend to solder it in (guide 1, guide 2). Five minutes later I was back to playing Street Fighter III - Third Strike.

Points to note:

• If your no good with an iron you might bust your Dreamcast, so attempt at your own risk.
• If you use a standard carbon resistor instead of a fusible resistor keep an eye out for smoke if the resistor blows again.
• The F1 resistor to replace may be in a different place to the position shown in the guides.
• Some people have just used a wire instead of a resitor which they claim works like a charm, this may or may not be a good idea...