i would suggest going to the great graphic resource thread. and looking at the free 3D modeling programs.
than go to the 3D tutorial section of the same thread. and just kinda pick a simple looking tutorial to follow. most programs have basic ui tutorials that you will find some where on their site that will help you with that if you don't find any tutorials for your program. you will still learn a lot from tutorials even if they aren't specific to your program.
basically just start making stuff. as you get better with the program start using reference images and try getting details more precise. and that's about it. other than just working on the models and continuing to model.
(don't be afraid to ask specific questions)
and also as to actual programs Blender has a Great community that would be very capable of helping you get started if you choose to use blender.
[url]http://myportfolio.x10hosting.com/[url]
visit my site.(still in progress)