By holding down the Control key on your keyboard and hitting the arrow keys you can jump to the extreme points of each worksheet.

For example hold down Ctrl and the down arrow will take you (in a blank Excel 2002 worksheet) to A:65536
While still holding down the Ctrl key and hitting the right arrow you will be taken to cell IV:65536
Ctrl up arrow will then take you to cell IV:1
And Ctrl left arrow will take you back to cell A:1

So there you go you have just done a quick trip around the four corners of your worksheet! YAY

Jon

Here are another one in the same context:

To go to the end of a column or row: Press 'End' key followed by the direction you want to go on the sheet and you'll go to the end of a continuous column or row with info (it goes to the first blank cell it finds)

If you trap the above during the recording of a macro, it works great in a number of different applications.