If you are not using PDO, you need to wake up

If you are still using the mysql* functions to access a MySQL database when writing new PHP scripts, you seriously need to wake and realize this is 2013 and not 2004. The old mysql functions are not being maintained anymore, lack support for the latest MySQL features and -if not carefully used- are prone to security problems.

Then what should I use instead?

It's simple: a more modern interface such as mysqli or PDO. And for most projects, I'd recommend PDO.