I'd say its a scam for sure, I had a friend who had a very similar offer and the would be employer even said they wouldnt need to worry about a visa application as they'd sort it all out. The apparent employers' english was pretty bad as were his credentials and he became very short of temper when questioned further about the alleged position, turned out it was a Nigerian scammer in london using a few different addresses. I dont think any legitimate employer will ask for any processing fees etc up front. I'd suggest getting as much information on the person as possible, ie how and where to pay the money and pass it on to the authorities.
I'm actually just recently applied for a job in China through a legitimate recruitment site and had a very fast reply from the firm placing the advert saying my CV was very impressive...all seemed a bit over eager, having googlised them all I could find about them were recruitment adverts on pretty much every job site in the UK, I sent a reply and just waiting for them to ask me for some processing fee to open the gateway to my 'dream £60k+ per year job' On the other hand I might just be a bit over suspicious and jaded, but there a lot of robbing b'stards out there so I'd rather be that way than robbed.
