With luck it'll pay for your hosting costs. If you don't have an Adsense account you'll need to set one up here. Go to your Google account page, select an ad configuration and copy the code Google creates for the ad display you want. You need 120 or 160 pixels wide if you put it in the sidebar. The one here @ my wits' end is 160 px wide.
- Go to Admin » Appearance » Widgets.
- Drag a Text widget into the position on your Primary Widget Area that suits you.
- Paste the code into the Text box.
- Wrap <center> </center> tags around the Google code as shown below to centre the ad in your sidebar. Otherwise it lines up on the left and will probably look off-balance.
- Click Save.
It may take a few minutes, or even hours, for Google's spiders to cotton onto your pages. So don't assume that a blank box is a sign that you've blown it. 🙂