There are a bunch of modelling programs listed in the sticky posts exactly for this kind of question. They list pros, cons, costs, ease of use, and various links.
DoGA CGA is probably the easiest of the bunch since it uses a parts bin metaphor (think virtual Legos or Technics), but it is not the best for making game models. Game models should be meshes and not collections of parts. DoGA can be used as a designer, and then the model cleaned up in Metasequoia LE, Milkshape, or some other low level polygon editting tool.
You can find links to all these tools and more here:
http://forum.thegamecreators.com/?m=forum_view&t=25468&b=3
--
TAZ
[edit for typos]
"Do you think it is wise to provoke him?" "It's what I do." -- Stargate SG-1