Google announced you can now use a single sitemap file for all the various content types. Vanessa Fox has the best analysis of what this means to webmasters and other search engines at Search Engine Land.
In summary, it may lead to making things easier for SEOs and webmasters to worry about a single file. But sometimes, it makes sense to keep them separate. At the same time, it is questionable if Bing and other search engines will support this or not. As Vanessa said:
A lot of work went into the launch of that alliance, with the goal of making things easier for content owners web-wide, and not just for one search engine. So the partial dismantling of it, even in spirit, is a bit disappointing.
So will this confuse webmasters and just benefit Google? Time will tell. I guess the other search engines can just follow Google's lead?
Forum discussion at Sphinn.