If your arrow keys are not working in Excel, there are a few simple ways to troubleshoot and solve this problem.

These are OS X-standard cursor control keys, and they should work in most any application (exceptions include Microsoft Office 2004 and 2008) that involves text.

The cell immediately enters edit mode, placing the cursor at the end of the content. You can instantly start typing to add more information, or use the arrow keys to move the cursor for precise edits.

Rob Griffiths offers up some keyboard shortcuts for moving the cursor about in the Google search box in Safari 4 Beta, as well as in many other apps on your Mac.