If you are noticing that your index count in Google Webmaster Tools in your Sitemaps section shows zero pages are indexed, then don’t panic. Google has confirmed in a Google Webmaster Help thread that there may be a bug impacting some reporting for Sitemaps files.

JohnMu of Google said:

This is not the first time Google had a reporting glitch with Sitemaps. A few months ago, we reported a similar issue. I cannot express how many times we have reported issues with the reports at Google Webmaster Tools. So, whenever you see something really out of the norm, I would strongly recommend you not panic and wait.

Forum discussion Google Webmaster Help.