Screen Printing?

This thread got my brain juices flowing. It seems that a clothing line is actually quite lucrative and also can be boot-strapped. My simple question is if someone were to purchase wholesale products and sell them retail, but wanted to print their logo/message on them, how would they go about doing this?

Let's think hypothetically you have a small budget and limited space (so you couldn't purchase a huge industrial machine.) What would be used to accomplish this? My guess is some type of printing. I've heard of screen printing but I'm unsure of what exactly this would entail for a start-up entrepreneur.

Thank you for your help.