Godzilla - MLP crossovers are very common occurences on Deviantart and Fanfiction.com
MLP The Bridge
The bridge is best known Godzilla - mlp crossover out there. The story is 60 chapters long and is about Godzilla and other kaiju finding themselfs stuck in the world of ponies. The main villain is Bagan and Spacegodzilla is renamed Xenilla for some reason. Another stange thing about the bridge is that the kaiju seem to be able to turn into ponies and back at will.
There are two major ships in the MLP Godzilla crossovers: Princess luna X Godzilla and Twilight Sparkle X Godzilla. These ships usually have the pony characters being in kaiju or human form and have them as big as a kaiju. In these fan arts the ponies kiss and love up with Godzilla.