In Solidworks 2008, you can select the pull-down menus WINDOW - VIEWPORT and choose the number and direction of the screen partitions. Another way is to use the new Heads-Up display palette at the top center of the part window, where the VIEW ORIENTATION icon also contains within it a list of available viewport partitions.
In SolidWorks 2007 and 2006 you could also click the yellow pull-down list in the lower left corner of the graphics window and choose "Four View".
Either way, once the screen has been partitioned into viewports, you can then place the mouse on the splitter bar and drag it to re-size the partitions. In Solidworks 2005 and prior, you had to look for the minimized display of this split bar (a small rectangle to the left of the horizontal slider or on top of the vertical slider), and dragging this would split the graphics window into multiple viewports.
