There is a list of official middlemen here:
The Official MiddleMan List - Updated 3/30/09
It has their msn's and price...
But they cost alot, and they have imposters (people that have similar emails and pretend they are the real) so ask for a PM on sythe
Trusted Middlemen are good but some can scam... If they have 15 - 20 trades, i doubt they will scam a pin
All trusted middlemen will have a MM application, just like mine if u click my wall in my sig..
hope this helps