This is on the memory card of your digicam? what you need to do is first....Don't take any more pics! then get yourself a card reader and an undelete program. then open the undelete program, select the drive where the card is and hopefully your pics will still be there.
try Active Undelete for this.
The reason is, when you hit "delete" it doesn't really delete the pics, it just marks them to be overwritten. so if you don't write to the card at all, you should be able to recover them because they'll still be there. This works with your hard drive on your computer too, if you accidentally delete something you need back, you can get an undelete program and recover it. but it's important not to write to the drive before you recover the data.