jameszol - 1:57 pm on Aug 20, 2012 (gmt 0)
via the AdWords UI:
In the global nav (dark green, upper left), click 'Campaigns' if you're not already there.
There will be a sub-nav menu there (pale green with dark green text) that lists campaigns, ad groups, settings, ads, dimensions, display network and a few others.
Click on the 'Ads' tab and there should be a Status column there by default. Ads may be stuck in an "eligible" state for 3 days. If they stay there, contact AdWords Support to get them approved. Otherwise, you should see "Approved" in that Status column if the ad is approved.
Alternatively, you can drill down by clicking a campaign, then an ad group, then the ads sub-menu again to review ads for a single ad group.
via AdWords Editor:
If you're using AdWords Editor, then the above sub-nav instructions are almost the same (without the color) with one note: Make sure you are viewing the most recent changes. Simply click "Get recent changes" in the upper left corner and you should be good to go.