I did that a few days ago. They used to be very good at closing down accounts but I've had no feedback and the account still appears to be live, as emails to it don't bounce. Behind the scenes, I've done quite a bit more which I won't publish here (PM me if you want to know) , but let's just say that these people will be having some problems with continuing to try to scam people with this particular scam. Of course they will just set up again and carry on but it does make life awkward for them and if it only saves one person then it's served a purpose.
I've had to protect the staff in my company, many of whom are expatriate workers, more times than I can shake a stick at from sending off a "processing" fee to a company that's guaranteed them a lucrative job.
I've even contacted the Met to ask for advice, and basically they say that they are so swamped with the ****ing things that they won't even look at it if it's less than a certain amount (5 or 10 grand) in losses.
Sad really - the simple solution would be to just cut Nigeria off from the Internet, they are without a doubt the source of most of these scams.
But the other solution is to educate stupid people in the old internet (and life!) adage: If it looks to good to be true, then it almost certainly is!