Modeling Homepage
There's a few things to keep in mind when modeling for Goldsrc related games. The best place to read up on these things is on The303's Website
For compiling the models it's required you use Svencoop's MDL compiler until we ship our own some day.
Modeling-Specific Tools & Links
Half-Life Asset Manager: Recommended .mdl viewer and can also perform MANY utility functions.
Blender: Free and open source 3D creation toolset, plus many other possibilities.
Crowbar: Decompile, compile, and view goldsrc + source models.
IrfanView: The recommended free image multi-format viewer and converter for texture needs.