Firefox does indeed store its cookies in an SQlite DB. A add-on for firefox: sqlite manager will default to showing you the installed DB's. Mileage will vary between browsers. Each will have its own separate cookie DB.

SQLite is probably the most used DB in the world. The Perl DBI can access this with standard SQL.

Update: I am currently working on an SQLite DB project. The firefox add-in that I recommended is great and I use it every day now.