hey i have got XomView v2.0 by Alex Bond, but i don't know how to use it.

please helphttp://i745.photobucket.com/albums/xx96/photobucketjp/img-bazooka-jpworms4-xomview-questi.png?t=1251115422

Well, I suggest you to download the 2.1 version of XOM View firstly. You can download it in two forums:

1) The official russian website of Alexbond
2) The forum of Wormsters clan

After that, you need to open the .XOM files you find in the different folders. I can teach you about changing colour of things, but for the 3D model Alexbond is the best here.
To change the colour you need to scroll down the input comands (they're at the center and are the coordinates, maya images, etc...) until you find a command that highlights the button export and import image. The preview of image will appear on the right below.
When you export the image, you can modify it and then replace with the original, giving new textures.

If you want to create from zero new weapons and clothes instead, you need Autodesk 3Ds Max (version 8.0 or 2009 recommended) and then search on Youtube Alexbond's video tutorial. In this last case, I can't help you.