Warning
Using Blender with the Source SDK is fairly complicated. Until cohesive documentation is compiled in the future, there is a set of videos for beginning.
Below is a series of videos on YouTube that serve as an introduction in creating models for the Source Engine in Blender.
Props are static models that are placed around maps.
Creating simple props
Exporting
Compiling
View models are weapons as seen by the player in first person (not third person.)
View Model Animation Part 1
View Model Animation Part 2
View Model Animation Part 3
Player models are used to represent players. LuminousForts uses the HL2DM animation system.
Player Model rigging