If you want to put a timestamp on records then use the Timestamp column type. Pay carefull attention to the parts about the timestamp data type that are version specific.
Unfortunately, with mysql, you cannot set the default value for a column to a function like NOW() - which is what one would do with other dbs - so you just get the zeros you've found. So, if you don't want to use the timestamp data type then you have to force the value into a datetime column by using NOW() in the insert query. Bit difficult with phpadmin's load text file functions, but you could recode it if it really matters. Best bet is to just use the timestamp column type, or write your own Load Data Infile query.
