Overview of tax lien investing?

[Brett Fitzgerald]

Hi everyone,

I recently listened to podcast #56 (http://biggerpockets.com/show56) and found the idea of tax lien investing very interesting. Is there an overview that goes a little more in depth as to the advantages, risks, and process involved with purchasing tax liens? I'm in west Michigan, and from what I can tell our state only allows the auction of the properties themselves after they are forced into foreclosure from overdue taxes, by the state. Is anyone aware if that is correct? Do only some states allow the auction/sale of tax lien certificates?

Thanks!

Brett