Single Sided Mesh Problems

I have been creating this mesh for some time now and have finally got to the stage where I wish to skin it. I have kept having problems however that I believe are caused by Blender or myself (I cannot work out which) making parts of my mesh single sided leaving me with gaping holes in thetexture and in someplaces the UV map itself.

http://allyoucanupload.webshots.com/v/2000600639752468259

I believe this is the problem however I am not sure (certainly when I select single faces and set them to double sided it corrects itself). Could someone confirm this, tell me how to fix it quickly (so far I seem to be only able to do it a face at a time) and perhaps how to avoid doing this next time round please.

With UVMapped textures you only see the side of the Face the Normals point. Ctrl-N with all Faces (or Verts) selected in Edit mode should point all normals out.

%<

That has done something but really its not helped. If anything now more faces are in the wrong direction :(.
http://aycu21.webshots.com/image/37580/2004615257001183010_th.jpg
Is there a quick way of making my mesh double sided, as that seems to work it just takes so long to select each face individually?

Blender has a hard time with a mesh like that deciding which is inside and which is out. Best you can do is select parts that are symetrically hollow, hide the rest, then Ctrl-N. Repeat till all are pointing out.

To make TwoSide make sure you have an Active Face (red and green lines on 2 edges) in UVFaceSelect mode, set the Active Face to TwoSide then click Copy Drawmode.

%<

To make TwoSide make sure you have an Active Face (red and green lines on 2 edges) in UVFaceSelect mode, set the Active Face to TwoSide then click Copy Drawmode.

Thank you very much. Thats worked perfectly, and finally my UV maps seem to be working properly.