ESRI has created hundreds of web courses and other training materials to help you learn ArcGIS and other ESRI products. ESRI web courses are:
If you are a member of the MIT Community, email email@example.com and ask for access to the ESRI training site. You can then browse all the offerings. Ask if you need suggestions for courses!
**Note that some training materials are not available for free, such as in-person training, certification prep, books, etc.