Hi and welcome to SPCR!!!
Here's some info about the fan used in some other models, and I guess there's a chance that it's the same for yours. I actually don't know.
Just be careful when choosing fan, and make sure that you can use a standard fan.
POSTSCRIPT, April 3, 2008: Not a PWM Fan
Here's something of interest that came from Enermax recently. It's regarding the fan, which shocked me with its smooth quiet performance in our review sample:
The new Enermax MODU82+ and PRO82+ series power supplies use a new patented SpeedGuard control circuit to achieve low fan RPM and extremely low noise without any negative effects. The patented control circuit requires a unique fan with a 4-Pin power connector, like a PWM fan. But this is not a PWM fan; it is a patented bi-voltage fan.
1. Enermax's new SpeedGuard control circuit does not require an expensive PWM fan; instead, they use a new special design fan which offers low RPM with higher CFM.
2. The new MODU82+ and PRO82+ series PSU fan cannot be substituted with a standard 3-pin fan or a 4-pin PWM fan. Doing so may cause the substitute fan to not run, run only at full speed, or be damaged. There is also a risk of damage to the SpeedGuard control circuit. The 4-pin configuration is not standard.
Conclusion: Do not modify ENERMAX MODU82+ or PRO82+ PSU models with any other fan (unless you have a very good understanding of electronics and you're willing to void the warranty). The fan control circuit in these new PSUs can only work with their own stock fan.
Your PSU is reviewed here, and I guess it's possible that the reviewer, Devon, wasn't aware of Mike's conclusion above.