New to Screen Printing

Hello All,
I have been interested in screen printing for a while and have been a consumer of unique shirts for years. I think I have found a niche within this realm, but need some more education before I embark on this new endeavor and invest in equipment.
I met with Printa for a tutorial on their business and equipment, but have read they are not necessarily the best and is very over priced- is that correct?
What are regulations when using pop culture photos (sports) for shirt images? Is there a time of demarkation when an image is for public use? Is Coral the best software to use or could you use Photoshop for all image needs?
I know about shutter stock, but is there other sites that screen printers use for images?
Is there a network to join for wholesaler connections, connections to graphic designers etc..
Sorry for all the questions. I hope these can be answered within this forum and hopefully make some connections as well.