Business offer of service letter security training

I am writing a letter to introduce my partners company to other companies, with the offer of services, and the possibility of commission.
Could anyone please refer me to a site with good letter templates and or examples.
My partners company deals specifically with physical intervention, restraint, combatives training and other types of security training.
The instructors are made up of Ex-military and Martial-arts Experts and we will be offering their services to both Security Companies (Door Staff, Night Security firms) and Specialist Security Companies, that provide Close Protection Operatives for example. So if there are any examples for that area out there, that would be extremely helpful.