Hi, I'm modeling a stock model and I need to make two side in blender work. I'm trying to make an interior to an exterior object so this is a rather necessary part of my work. Also, will two side work when I step on both sides in the game? Thanks for any help.

two side? What do you mean by that? If you mean what I think you mean, (to have textures on both sides of a face) the most effective way to do that is to put another face inside the building with the normal pointing in the opposite direction of the exterior faces.

Yes, that is the two side I'm talking about. There should be a way to do it using the two face option but I'm not sure how. Everytime I export an object with two face, It never loads with both sides textured.

i suppose the two-face option in blender is just some kind of rendering-related thing. to make walls etc two, faced you must hexedit them for two-sided, hardedged transparency, but as knightfire said, it is probably beter to make two polygons facing the oposite direction instead of one (dont make them too close to eachother, or vm could decide to merge them) because one poly can only have one-sided collision

Just make it have two physical sides (using two seperate faces). Objects with a width of 0 are very unnatural.
in case you don't know, there are options in the edit mode to flip the normals, recalculate inside, or recalculate outside. I'll give you a little example here, assuming you were going to make a simple tunnel with both interior and exterior walls. well, I'd start with a cylinder, but not cap the ends. Then I'd duplicate the object in object mode and scale the duplicate slightly smaller. I would then go into the duplicate's edit mode and select all the verticies, then click the "recalculate inside" option in the menu. I'd then go back to object mode, select both the interior and exterior cylinder, and find the menu option to "join objects" or "join meshes" or whatever. then I'd go back into edit mode and fill in the missing faces on the ends of the tube (by selecting the four vertices that form the needed face and pressing "f". When that was all done, I'd then go and select the option that lets you convert quads to triangles, and then after doing that, I'd uv map the model and export it out. Done! Of course, I think there is a "tube" option in the menu for meshes to begin with, so all that work probably isn't necessary, but I just used it as an example for how to do the same with something more complicated, such as a whole room.