Shade Alternating Rows in Excel:

You can use Excel conditional formatting to shade alternating rows on the worksheet.
1. Click the Select All button, above the Row 1 button, to select all the cells on the worksheet.
2. Choose Format|Conditional Formatting
3. From the first dropdown, choose Formula Is
4. For the formula, enter =MOD(ROW(),2)
5. Click the Format button.
6. On the Patterns tab, select a color for shading
7. Click OK, click OK