By default both vB2 and vB3 use the URLs with the ? & in them. However the way that vB3 does and vB2 with a hack will enable your site to be crawled is with an archive. To take a look at what I mean, visit the
vB3 beta site and click Archive in the footer to see an example.
There has also been discussion on the boards of making all URL's in the form that you mentioned, however I don't think its working 100% yet.
Hope that helps you out