Can I recover iphoto after having lost it/accidentally deleted it?
It's weird that an app just disappears like that! Are you sure it's gone? Before anything I would recommend you do the following:


Search using Spotlight (I'm guessing you already did this?) for "iPhoto".
Look inside your Trash. Maybe it was dropped there by mistake. You can always drag it  back out though if it's there.


If you do this but still find no traces of iPhoto, you can go ahead and re-install it. This can be done in two ways: 


If you bought your Mac before 2011, it should have come with two CDs in the box. One of them should be called "Applications Install DVD" (Disk 2). Slide that into the SuperDrive of your Mac, open it, and you should have the option to re-install iPhoto.
If you bought your Mac after 2011, it probably came preloaded with OSX Lion, and without any bundled software CDs in the box. If that is the case, you should be able to head over to the App Store and install iPhoto from there for free. This should also be the case if you ever bought iPhoto from the App Store. All the apps you buy from the App Store can be re-installed at any time for free.


Hope it helps! If you have any questions please add a comment below.