Is it secure to use mysql_insert_id

[Anon]

how about before the script run to the line
"mysql_insert_id( ..) " , Another user that logined in insert another row ..

[Anon]

mysql_insert_id() returns the last inserted auto_increment value of
the current database connection.

If you have two users inserting records at the same time, they both use a seperate connection. So yes, it is safe.