There are several techniques that you might want to practice, such as edging, ballooning, Kegeling right before you reach the point of no return, getting in touch with your arousal, and the multiorgasmic orbit. All of these will help you in the long run more than a pill ever can.
That said, Selective serotonin reuptake inhibitors (SSRIs)--such as Zoloft, Paxil, and Prozac--delay ejaculation for many men. They are typically used for depression, but a low dose a few hours before you have sex will often do the trick. You'll need a script, though.