1) How is the interest rate on the debt and what type of debt is it?
2) Is the debt still held by the original creditor or is it in collection?

So if the answer to # 2 is that it is still held by the original creditor you might be in luck. Try negotiating a payment plan with them that is reasonable and has reasonable interest rates. If this is not successful you might turn to one of the legitimate Credit Counseling services who can work with you and the creditor. They will negotiate the interest rate down for you and the payment plan. Usually it will be a three year plan, however there is nothing that says you can't accelerate the plan.

Going this route will not harm your credit report and over time will start to show improvement as the debt is serviced. Generally, the creditor will note the debt is being managed by a credit counseling service, however this is not as bad as the alternative.

Credit counseling services vary so do your homework before signing up. Personally, Consumer Credit Counseling Service (CCCS) is the most well established and has the best reputation in the industry. They, I believe can also assist with medical bill consolidation and payment plans.

You have a much different problem if your debt is in the hands of Collections and has been written off by the original creditor. In most cases the original creditor won't pull it back and negotiate. You might still try first to have a discussion with CCCS to see what they say. Collectors will usually offer you a one time payment option of something less than the full amount, be aware that this will not retire the debt and the negative will stay on your record for 7 years with the comment that it was paid "short". With a notarized letter from the original creditor authorizing the collector to accept short payment as payment in full don't fall for this.

If you have collectors coming for you and can't negotiate with the original creditor your options are limited really. You can try to work out a payment plan with the collection agency, you will get hammered with higher interest rates and collection fess likely to exceed 50% of the original debt. You can talk to an attorney about bankruptcy (reorganization) which may solve the problem but will stay on your credit report for 7 years, but then so do the collections.
References :
http://www.nfcc.org/
http://www.cccservices.com/