The long answer is this: Homeschooling, or educating your children in a manner and place OTHER than in a State Public School, is legal everywhere in the U.S. There are, however laws, regulations and, frankly, hoops some parents must go through in order to assure the state your children are being educated.
Here's the good news! In Indiana, those hoops are almost nil! Indiana is one of the top 5 best states for homeschooling freedoms.
Check out the "New Homeschoolers" section of the IHEN web site for more detailed information. http://ihen.org/IHEN-NewHSers/
Links:
IHEN.org
IndianaHomeschoolers.com
IHEN Statewide Resource Directory
IHEN Mail Directory