Pool.com sends out an email of their "Hot List" every day with a list of expiring domains (http://www.pool.com/hotlist.aspx?ia=hotlist). They send about 30 domains a day, and I guess in an average week 5 are interesting and you can register for them at the various auction sites (Pool has no guarantee of getting them on the drop) and then bid on them. Very few domains that are usable go for less than $100 though.

Not as good as Ryan's AI but a nice easy way to occasionally catch a good domain.