I'm going to play it safe and say it's hinting to a sequal.

Looks like a big number 5 on it.

And I was thinking maybe Pikmin on the moon myself

That's the first thing I saw too.

If you look at the bottom of the moon you'll see a "P". Easier to see when its inverted. Next to it looks somewhat like a smiley face. Don't know what that means but its definetly something added into the pic.

Here's what I'm talking about. The image has been inverted and then a small area taken out. You'll need to put it on your PC though to increase the size:



Anyone know what that is.

I will say Earthbound

I see something that looks like a silhouette of sonic's face, in the top right of the moon.

maybe has to do with metroid trilogy....??

You guys have it all wrong. You must turn the moon upside down and look at it with a mirror. Then you will see... nothing!

 except that is actually on the moon, look at the pic on page one.  so it isn't like the put it there as the hint.

 havest moon seems a little to obvious, if it is as one poster mentioned, Lunar, my friend will go nuts and camp out at a store to get himself a Wii.