Some helpful 3D modeling overviews and tutorials:

• • Modeling Creation Overview (On Valve Developer Community wiki (VDC).)

  • Character Creation Overview (On VDC.)

  • Creating a Basic HL2 Character Model Using XSI (XSI aka Mod Tool. On veazie.org.)

  • Character Modeling (Several parts/pages on how to model a humaniod from scratch using Mod Tool aka XSI. On "Jailbreak: Source - Source SDK Development Blog".)