Hi Dustin,
The properties listed for sale by a Realtor on the MLS are all on the internet. They get pulled through on the back end and show up on Zillow, Realtor.com and any other website where you see listings for sale online. What you are seeing on these sites is the public version, it does not contain the confidential remarks that are only available to Realtors or any documents that are attached to the listing such as property disclosures and inspection reports.
I wouldn't advise getting a real estate license just so you can have access to the MLS, there are easier ways to get that access. I also wouldn't necessarily advise you to get a real estate license in order to learn the business of being an investor. Getting a real estate license is going to take you a lot of time and headache and teach you to how to pass a state standardized test and avoid going to jail for legal violations, thats about it. People really learn the real estate world after they get their license and start working at their brokerage.
You don't have to have a real estate license to be a real estate investor, and most people who invest don't.