Modern Draft?

Although I've been in the DKos community for nearly four years, I'm not a diarist and I doubt anyone knows me. But nagging concerns about a military draft motivate me to actually make a diary entry asking for info from those of you with knowledge.

Kos had a post a couple of weeks ago about the recent raising of age limits for military recruits, but it's been awhile since I've seen anything factual about the possibility of a draft in the future as our troops sag and things show no signs of improving. The "bring 'em home" talk goes on and ChimpCo just yesterday floated the notion that withdrawals may start in October 2006. I think that's B/S.

I have a 20-year-old son and 22-year-old daughter. I would like to know substantive info about what is involved to begin a modern draft. What would the process entail? Bush by fiat? Congress declaring? Both houses? By votes? What role is played by the Selective Service? Wikipedia and dKospodeia are respectively too broad and too narrow to get a feel for the "could-it-happen?" sense I'm looking for, both realistically and politically, to discuss this with my kids. I'm sure this informed community can help. Thanks.