Just really have to say how much I love this app! It's called 'Couple' (but you can also find it under 'Pair').
If you both have Iphones or just phones with touch screens it's amazing but it also works if you have a tablet/Ipad, so yeah.. anything with a touch screen that has internet and can download apps...
You can send each other pictures/videos/voice messages/drawings and you can do a bunch of other stuff. The cute thing is that it's just between you and your girlfriend/boyfriend so it's just about your relationship.
Best of all : It's free!
Really cute idea!