Been reading good things about the biddingfortravel site. Don't know if anyone here uses this service.
Basically this site helps to facilitate ordering with priceline. Very good for hotel deals if you don't have a specific hotel you stay at. It is good for flights too, if you are flexable enough (ie: standbye ete). I may be trying them out this year.

Read the FAQ's before using the service. More you know, less chance of messing it up.
http://www.biddingfortravel.com/

-jel