In my opinion it is best to send an email and meet for lunch with the potential investor, then just make a scheme of the project and ask if he/she would be interested in it.
Most business angels in here (Spain) advice against being afraid of your project being "stolen", as they find it illogical. They have a lot of private networks, like Acció Xarxa d´Inversors Privats, AEBAN (Spanish Assotiation of Business Angels) or BCNba (from Barcelona). Even if the main ones might not be interested in adult (or they may, it depends), you can have some names for the network to follow and they will probably send you to someone that will.
I don´t know a lot about other networks outside of my country, but I think the research may as well start in the main concentration, if not by private connections which are normally far better. It depends on the project you have.
Anyway: good luck
