Here is a free macro, suitable for SW2005 and up, to export your models in Alias|Wavefront .obj format complete with .mtl and textures.
The macro works with parts and assemblies and configurations.
It has been made to enable SolidWorks models to be rendered in cg applications such as Blender http://www.blender.org/ and Octane Render. Octane Render As of the time of this post Blender 2.62 and Octane beta2.57 are current.
Edit: The Blender python script included with this release isnt suitable for 2.63. An updated script for Blender 2.63 and 2.64 is posted below.
This exporter comes to you courtesy of karpena, who wrote the basis of the macro, and yours truly who extended it and gave it a UI.
The zip contains the necessary files and instructions.
This macro wont as a rule be supported but if there are teething issues with this release please report them here.
KNOWN USE ISSUES:
-If you have 64 bit and find the macro UI launches behind the SW window press ALT+Tab to bring it
to the front.
-Be sure that your system is set to use decimal points and not commas in numbers ie it writes
0.9987 and not 0,9987 in the .mtl and .obj else there may be problems importing the files into
other applications such as Blender.
-Beware that using non latin characters in file and folder names may cause issues with textures
Edit: 6 Oct 2014
AFAIK the blender script provided for 2.63/4 is still ok as of Blender 2.71 and for at least Octane 1.55.
Assistance for this macro is no longer being provided by the author but someone from the community probably will do their best to help you if you have questions or issues. Thanks for everyone's interest and downloads since it was first posted.
Edit 8 Oct 2014
added short video by Deepak Gupta (thanks) to attachments showing how to install and run the macro.