Typically I have seen project manager "generalists" make up to $110 with a few as high as $115K. For a specialist like myself, it depends on the specialty.
In my specialty (PMOs and MOPS 2007), I generally see salaries in the $130 to $150K range.
All this also depends on if you are a contractor or an employee.
As a contractor, I was making $170K in my last position.
What skills? Master the PM Triangle, Digest PMI PMBOK, and then remember that those are just the "tools". To be a successfuly PM you must understand the political aspects as well as the communication needs of your stakeholders ALL OF THEM..
What most PMs that I have trained forget are those stakeholders not originally identified as part of the project. Typically you ask about who the stakeholders are... then you compile a list... and then do the project, right?
Stakeholders change throughout the project. You must seek out people who are impacted by the project, whether they know it or not, and activly involve them. When they don't want to be part, you have to sell them on why they need to and then determine the minimum level of commimtment and communications...