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:
It looks like the "0" count may be a bug at the moment, so I wouldn't worry about it for now. I looked at your Sitemap file and some of the URLs are indexed. Because of that, I imagine that this is just a case where what you want indexed just doesn't completely match what Google wants indexed at the moment :-).
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.