While some interaction (UX, User experience) designers went to school for industrial design, I would not say that Interaction design is a sub category of ID. Each discipline requires different skill sets.
In a nutshell:
• Industrial designers- design products (cars, electronics, furniture, etc)
• Interaction designers- design interfaces(Web, Mobile, Application, etc)–Although they also design the interaction between the user, the product and the interface. I.e. Bank patron-ATM-Interface.
To become an Interaction designer you can either go to school for it, or self teach and get an internship. Some of the programs for Interaction design can be called HCI (human computer interaction) or UX, etc. I believe there is a list of schools in this forum that offer programs. If not check out http://www.ixda.org/ for additional resources.
Also, check out some books:
http://www.designinginteractions.com/
http://www.amazon.com/About-Face-Essentials-Interaction-Design/dp/0470084111
Also check out:
http://www.cooper.com/insights/concept_projects/