Hopefully by the time you read this post, the issue will be resolved. However, yesterday afternoon, a Google representative, JohnMu said there is currently a display issue in the Google Webmaster Tools.
A Google Groups thread reports several webmasters who have submitted their Sitemap files days ago, but the Sitemaps file status is still in the status of "pending." Typically, a sitemap file should be accepted within 24 hours.
JohnMu of Google said:
This is currently a known issue, the team here is working on resolving it as quickly as possible. Generally speaking, it's normal for some sites to take a while before the "pending" status disappears. At the moment however, it looks like this is taking a bit longer than usual.
If the "pending" status for your site has been showing for a while now, I wouldn't worry too much about it for now. It's not something on your site, or anything that you need to resolve on your end.
I'll update this thread once it gets resolved. Thanks for your patience!
Forum discussion at Google Groups.
This post was written on October 8th at 1:30pm (EST) and scheduled to go live on October 9th.