is there a way to recover deleted data on mobile phones/memory cards.
 

I used my phone (nokia n82) to take alot of pics at a car show, and they all randomly deleted themselves without me doing so?

Is there any way of getting them back?

yep - couple of things.

Have you tried putting your memory card into a card reader and viewing it on a computer. It may be that the phone is misbehaving and cant read the files.

Failing that - I would put the card in a card reader and run something like this Free Undelete SD Card download