Hello, I am currently trying to add throwing weapons, like spears, into Fallout 3, from using the Fallout: New Vegas Resources I already have. Don't worry, this is a personal mod.
I have gotten most of the weapon finished and ready, the only thing I am missing are Attack Anim and Animation type. Fallout 3 doesn't have the correct ones for the throwing Spear. I thought I would just add a New Attack Animatino and Animation type into the GECK for it to be used, just like Projectile, but no matter how much I look, I cannot find it. Can anyone tell me if this is possible to add in the GECK, and if so, how?

As far as I know, there is no way to do this. The animation types are hard-coded into the engine. You can fake it through scripting. Check out Skycaptain's http://www.tesnexus.com/downloads/file.php?id=8273 mod for Oblivion for inspiration.