A lot of mobile phones can be setup to emit a reminder beep every few minutes if you have an unread SMS.
So when you miss the receive signal of the sms (because you've been in the restroom) you'll hear a gentle beep every few minutes, so you know you received an sms while you've been busy.

Is there a way to get this behaviour on windows mobile (6.5)?

I found nothing to activate this in the menu, but maybe it's hidden somewhere. Or do I need an extra software (but where could I find this?)?

Thanks, Sam