Not many people know it, but debt collectors are not supposed to call your cell phone. That's part of the Fair Debt Collection Practices Act, but it may change soon due to the proposed deficit reduction plan. Certainly many people don't have landlines any more and this is the only way to contact them, however, it's not been widely publicized.
Everyone hates debt collectors, I suspect even debt collectors hate other debt collectors. They tend to make lawyers look good. But unfortunately, their job is essential and one way to avoid them is to pay your bills. I know, that's easy for me to say and a little bit callous. To protect the collectee, there are rules that collectors must follow. A lot don't and the FTC says there were 140,000 complaints against debt collectors last year alone. I suspect there were a lot more issues that never got reported. Many people won't register a complaint because they know they legitimately owe the debt.
Bankrate.com does a good job of explaining this change and lists some of the guidelines debt collectors are supposed to follow in this posting.
According to this report from Fox News, "apply only to cases in which money is owed the government." I guess we'll know more as the details come out