On top left side of the worksheet, there is an 'Name Box' (just left to the formula bar) that shows address of the current cell, click on that, type the cell address and your cursor will move to that cell.
In addition to what posted previously and more than correctly, if you're using Excel versions 2007/2010 maybe you find useful this: Start tab, Modify (Update?) group -the one who contents sort, filter, find, replace... sorry but mine's in Spanish-, Find and Replace icon, and then Go To Special. There you have a lot more of options to navigate thru a worksheet.