If the pdf has vector content you can do a "print to svg." Instructions are here on my blog
http://cleversomeday.wordpress.com/2010 ... -cutfiles/
Keep in mind that some vector files are not suitable for cutting, but for those that are this is a great way to extract the vectors from a PDF with no added nodes or loss of quality from tracing.
If the pdf has raster(bitmap) content then you can take a screen shot and save it to jpg and then import it into SCAL2 to trace. If you don't know how to take and save a screen shot there are instructions here
http://graphicssoft.about.com/od/screen ... s_Tips.htm
The best way to tell if a pdf is a vector or a raster is to zoom in, say 300% and if the lines are jaggy it is a raster. If they are smooth it is a vector.
Both of the above techniques are great to know because they allow you to convert so many things to a SCAL-ready file.