Here is a useful summary of some of the issues and a nice graphic that compares and contrasts different provisions of House and Senate bills.
Here is a short article describing two sources of fear: government and private insurance companies. Interestingly, they cite a poll that says 40% of Americans fear government more, 40% fear private insurance companies more, and the rest not sure. I find the fear of government as health care payer to be a bit of a cultural puzzle. Medicare (what you have if you are age 65+*) is a federal government insurance plan that is primarily tax financed. Medicare provides (and always has) absolute choice of doctor and hospital. My private insurance (which is quite good) doesn't even allow me to go to UNC hospitals which is 7 miles from my house (Duke is about 2 miles from my house). I can go to any doctor--so long as they are on the list provided by my insurance company. But, many docs near my house are not on the list. I like my doctor just fine, but he was assigned to me when the docs I kept asking for who were on my private insurance compnay list weren't taking new patients. I finally said to my private insurance company, why don't you just assign me one, and they did. And I like him.
On the issue of denying care. One of the reasons that Medicare is in trouble financially is that it does almost nothing to limit what doctors and patients decide to do in terms of care, so long as it is not experimental. Private insurance typically provides for numerous steps to get care approved. Medicare does set rates of payment for doctors and hospitals, and eventually cutting too much can cause access problems for beneficiaries, and again, leading to cost problems because if you set the payment rate but do nothing to control what is done, this is not conducive to holding down costs, and can actually incentivize a provider to do more.
Finally, the most bizarre aspect of the reform debate are the various pictures/accounts I have seen/read of Medicare beneficiaries saying to keep the government out of Medicare. Just to repeat, if you are a Medicare beneciciary, you are covered by the largest tax financed single payer (aka socialized medicine) in North America. There are more Medicare beneficiaries than Canadians.
*Medicare also covers persons with end stage renal disease (regardless of age); and persons who are permanently disabled.