For a bill like “Obamacare” to pass the Senate it must first be brought up for consideration and debate for the entire Senate. This takes 60 votes. At this point amendments can be considered (Nelson's point). I believe this will take place tomorrow (Saturday, November 21).
Debate continues on the bill until they vote to end debate, requiring 60 votes. If they can't get the 60 votes, it is effectively filibustered. The fact is that they could continue to modify and adjust the bill through amendments until Nelson, Lieberman and other Blue dogs accept the changes (and promises for money to their states...).
Once Debate is over, it takes 50 votes to pass.
There may be more arcane parliamentary do-si-do's available. If you hear of anything, please let me know.