Hedwig has posted many times about the "Rule of 78" interest computation, and there always seems to be questions. This is a good article reviewing the subject, and what it means to you. http://www.bankrate.com/brm/news/auto/20010827a.asp
Thanks, Biz. That's a good explanation. Basically, if you got into this type of loan, don't bother paying earlier or refinancing--you'll end up paying double interest that way. Instead, if you're in this kind of loan, take the extra money you'd pay and put it in an interest-bearing account. But DON'T spend it, or you'll never get ahead of the game.