Order By Timestamp quick question

[Demonic]

Ok I've created a table with timestamp in it.
Ive completed my forum software almost i need to make it so when i make a topic it updates the time topic was made so i can fix my viewforum and do a

[code=php:0]
$bam = mysql_query("SELECT * FROM mytable WHERE fid='$blah' ORDER BY timestamp") or die(mysql_error());
[/code]

so how can i make my topic script update the timestamp with a real date then i can do my code above.

Thanks in advanced.

[hitman6003]

[code]$query = "UPDATE mytable SET timestamp = '" . time() . "' WHERE fid = '$blah'";[/code]

[Demonic]

thanks im gonna do INSERT INTO though thanks :)