Here is a nice free website on how to do silk-screenign if you cannot find anything in your area. Nothing complicated.
I can understand that you would like to add screen printing as an option for your customers, and the previous answer gave you a pretty detailed synopsis of the process.
I would however, suggest that your company consider outsourcing the products you want to have screened, at least until you can determine that it is something that your customers would like to have on your items. At least then, you can determine the demand.
Most screen printing companies only charge a screen charge, typically $25.00 and then so much per item. One thing that the previous answer didn't address was the different types of ink for different applications.
Can your item withstand the high curing tempratures? If not, then a specialized in will lhave to be used. How many colors are you planning on? Each color will require a seperate screen.
Outsource your first few, and you will have a better idea of what it will take to set up your own screen shop.
Best wishes, and good luck.