You can't just print to PDF from OS X either - the page will still be broken up. So what I do is create a custom page size thats just the right width and height for the web content and then print to PDF...
Page Setup > Custom Page Size
... but wait there's more. I found out that even after creating a custom page size in Safari and then printing the page to PDF - I was still getting more width than I had specified in my page size - displaying the web content with white on the left side. What I discoverd though - was that if you shrink your window in Safari to the exact width of the web content - the Print dialog honors that and only prints the web content.
I suppose this could be used to zero in on a certain portion of a web page and print only that section too.

