Arpi,
The way that IO think you are looking for is to when createting the TIMESTAMP column, set the Default to be 'now()' This way ..
whenever you do an insert and leave out that column, it will auto insert the timestamp for you..
eg: (this is an Audit Log I use)
sal_id int(4) PRI NULL auto_increment
fk_sai_id int(4)
sal_audit_date timestamp(14) YES Def.=now()
sal_comment text
INSERT INTO system_audit_log (fk_sai_id, sal_comment) VALUES (1, 'Bad thing happened');
And i get back ..
+--------+-----------+----------------+-------------------------------------+
| sal_id | fk_sai_id | sal_audit_date | sal_comment |
+--------+-----------+----------------+-------------------------------------+
| 255 | 1 | 20011107060318 | Bad thing happened |
+--------+-----------+----------------+-------------------------------------+
Hope this helps