Every county is different and it varies every year. However, tax-lien-database.com uploads listings from each county they make available. Currently they have Kent and Sussex counties available, but you can ask them for any others and they'll upload it for you.

Each county is different. Reference the web pages below. NCC you have to buy the list from the Sheriff at 800 N. French St, Wilmington. Kent and Sussex county publish the list online. You cannot view these properties prior to sale, except to do a drive by. All properties are purchased “as-is”. Check with the Recorder of Deeds in each county to see what liens are on the property. Good luck!

New Castle County:
http://www.co.new-castle.de.us/sheriff/home/POS_TBLTOPIC_Att…

Kent County:
http://www.co.kent.de.us/Departments/RowOffices/Sheriff/sspr…

Sussex County:
http://www.sussexcountyde.gov/dept/sheriff/