For general information on homeschooling, www.homeschoolingonashoestring.com is a great place to start. On the right side of the page is a section titled Homeschooling by Subject. Listed are ideas and such for those wanting to save money while maintaining a high quality of education.
For local information, visit HomeschoolingMichigan's website at www.homeschoolingmichigan.com. There you will find activities, links to other groups, and general homeschooling information. For information on different methods and philosophies of homeschooling start here: http://www.homeschoolingonashoestring.com/homeschooling.html
For information on the legalities of homeschooling in Michigan, you can go here: http://www.homeschoolingmichigan.com/Michigan_MDE_info_excerpts.html In short, homeschooling in Michigan is completely legal. You are not required to register with the State or your local school district. You are not required to do any testing. There isn't anyone who sets it up. You do it yourself. The only fees are what you spend on whatever materials you find your kids learn best with. You are free to homeschool however you choose. If your child is currently enrolled in a school, it is a nice courtesy to inform the school that your child will now be educated elsewhere. It is up to you to decide if you want to inform them you are homeschooling, you are in no way obligated to do so.