People don't really store "check box list values" in databases, they store data, well abstracted from your UI.
Basically, what you need to store is some Boolean data, but, as this is not an individual Boolean item, but we remember that you work with some data mapped to a check box list (you better map it correctly :-)), you might need something better packed, as Boolean information is essentially one bit.
This is a nice short article on this topic: http://www.sqlusa.com/bestpractices/bitdatatype/
I have no idea on your database schema
to advice more. Perhaps, the real advice would be: use ADO.NET. :-)