Is there any way to compare the traffic to two different pages on the same graph in Google Analytics? I want to see how Page A compares to Page B over time in terms of number of pageviews.
I don't know of a way to perfectly compare two pages stats in the same chart in Google Analytics with Custom Segments, but you can get very close. It's not super convenient, but you can create a custom segment for each page you want to compare with the criteria:
Include | Page | Exactly matching | /page_url.html
Then filter your report with Advanced Segements to only show data from those two segments, and you have a comparison chart.
The catch is that the Page segment shows you all visits that included that URL, not raw hits on that visit. So the numbers for each will include the other pages visited by that user as well. (See http://www.google.com/support/forum/p/Google%20Analytics/thread?tid=5995c74e098cd526&hl=en)
However you can get even closer by applying an Advanced Filter on those results with Include | Page | Matching RegEx | ^(page_url.html|page_url2.html)$
Then the numbers for each page will still include visits where the user visited both pages, but all other pages will be filtered out. That may be as close as you can get directly inside GA charts.
apostlion is correct in that the two pages' stats cannot be compared with a Google Analytics chart, however, you have the option to export data (based upon the timeframe you specify) from the Content > Top Content section (use a regexp filter like "page1$|page2$") to a variety of formats and, if you follow the path of least resistance, you can compile plenty of fun Excel charts from the output.