Know anything about those "Seized Vehicles" auctions?

You see the ads all the time. You can get information on where auctions are held to dispose of government-seized vehicles for pennies on the dollar. Have any of you actually been able to get some useful information from these advertisers? I suspect you have to pay them to get on a mailing list or to obtain a list of some sort.

Let me know if you have had any good experiences with this.

Thanks,
Jerry