This may be browser-specific. I currently have open in Acrobat Reader a 22 page document with page numbers starting with 102. In both the page number box in the toolbar and View > Go To > Page..., I can enter either the document page number (say, 107) or the relative page (6) and jump to the correct page. When physical and virtual page number ranges overlap (and the number I type is ambiguous), I'm not sure how AR decides.
To do this, I think you need to turn on the pdfpagelabels option in hyperref. See, for instance, http://www.tex.ac.uk/cgi-bin/texfaq2html?label=pdfpagelabels. Paul
