The edges of the gun shouldn't be a problem after you export, cuz there is a auto smoth.
But if you want to make it rounder i suggest making a vertex in the midle of the gun and maving them out. (or moving the mesh in)
"i textured it within milkshape, im just wondering a good way to texture things cos milkshape seems prety limited."
Do you mean unwrap?
If not this is a good texturing program.
http://www.gimp.org/ (Didn't use it but i hear good things)
If you need unwraping tools.
http://www.polygonal-design.fr/e_unfold/index.php (also did't use it but seems good)
There is a free version.
[edit]
If you'r gun is 100% flat you can extrude so you get the midle vertex without too much work.
![Razz :P](./images/smilies/icon_razz.gif)