If you login to your Google Webmaster Tools account and notice that Google is reporting that they have indexed 0 of your submitted pages through Sitemaps, then don't worry - you are not alone.
A WebmasterWorld and Google Groups thread has several webmasters who have noticed the same issue. I suspect it is either already fixed or that it is impacting a select number of accounts. I personally do not see the issue when I check some of my sites.
Clicking on your Sitemaps section might show something like this now:
Total URLs: 171
Indexed URLs: 0
Total URLs would be the number of URLs submitted to Google via Sitemaps. So yours may be larger or smaller.
Is this still an issue for you?