Google now let you use spreadsheets directly in your AdWords account. You can access spreadsheet edit mode from the Keywords tab in any ad group, under the More actions menu. In the past, you might have used power posting to enter your keywords with bids and destination URLs. Now, with spreadsheet editing, you can accomplish the same tasks from a spreadsheet view. Even if you use another spreadsheet application, it's very easy to transfer your work into AdWords - simply copy and paste directly from your spreadsheet into your account. You can use formulas to edit your keywords and bids.