I found this great debt reduction calculator on bankrate.com. You plug in all your debt information (vehicle loans, credit cards, etc) and it gives you a customized payoff calendar or "schedule". You can put it information like "windfalls" (like tax returns, bonuses, etc) and extra money you can free up by cutting costs during the month.
It's a bit involved, but well worth it! (it took me less than 15 minutes)
Anyways! I used it and I really like it. Here is the link:
I hope someone finds it helpful!