Drop Down Menu in SharePoint 2010

I currently administer a 2007 site and am looking to replicate in this 2010... only problem is that I'm a novice user of SharePoint.

Within the 2007 site, I've sub-sites / pages showing as a Drop Down Menu from the Global Navigation Bar (top menu). I'm looking to replicate this within SharePoint 2010 site but cannot seem to work out how to do this.

Any help is much appreciated.

Thanks in advance :o)