HELP NEEDED- I do not know how to export a blend file to Counter Strike:Source.

Please can someone tell me how to export a weapon from blender to CS:S?
I started using blender because i wanted to model weapons for CS:S!
I am sure you can use blender to create models for CS:S , as it was recommended in a list of free programs for CS:S modelling on www.fpsbanana.com (CS:S customization site). PLEASE HELP!
I have only been using blender for a few days, but am already fairly good, as i have had exp with other 3D programs.:no: