From the pdf file showing all poll data:

Would you favor or oppose creating a public health care plan administered by the federal government that would compete directly with private health insurance companies?
9/09**
8/09
7/09
Favor ................................................
46
43
46
[217]
Oppose .............................................
48
47
44
Not sure ..........................................
6
10
10

The September results, therefore, show 46% in favor and 48% opposed. If the question is worded differently, the exact figures differ, but again, there is more or less an even split.

The problem is that it will require 60% of Senators - not 48%, or 53% - to overcome a filibuster, and this is decided on a state by state basis rather than a national referendum.

Even so, reform opponents are not directly attacking the public option, but rather a "government takeover", which most people oppose, or "bureaucrats coming between you and your doctor", which most people also oppose.

I think it unlikely that the public option will survive in its original form, but I do expect that some variant will emerge, either in the form of non-profit cooperatives (Baucus, Conrad), or a public option "triggered" by excessive costs (Snowe). The Snowe proposal is quite interesting. She is a Republican, of course, and so her vote would make the legislation "bipartisan", providing cover for reluctant Democrats. She envisions a public option not on a national level, but a state by state level, triggered by cost increases that reach a threshhold in terms of a percent of a family's income. Since the current trajectory strongly suggests that her proposed threshholds will be met sooner rather than later in most states, the triggering would likely be widespread and result in a de facto public option in many areas. This may be weaker than a single nationwide plan, but the details should be explored, because the idea is promising.