you give a name to the select box. <select name="blah">
then you give a value to every option. <option value="1">one</option><option value="2">two</option>
and when you insert it into the table you just use the select name value as the variable. $blah
the chosen option value (let's say "one" was selected) will be inserted. in the case of "one", "1" will be inserted.
hope this helps