Yes. In addition to submitting your Sitemaps to Yahoo! Search through Site Explorer, you can:

• Send an HTTP request. (Send using our ping API)
• Specify the Sitemap location in your site's robots.txt file by adding the following line: Sitemap: <sitemap_location>
  The <sitemap_location> should be the complete URL to the Sitemap.
  For example:
  Sitemap: http://www.example.com/sitemap.xml
  This directive is independent of the user-agent line, so you can place it where you like in your file. For more details see www.sitemaps.org.

Yahoo! Search retrieves your Sitemap and makes the URLs available to our crawler. Sitemaps discovered by these methods cannot be managed in Site Explorer and do not appear in the list of feeds under a site.

Note: Using Sitemap protocol supplements the other methods that we use to discover URLs. Submitting a Sitemap helps Yahoo! crawlers do a better job of crawling your site. It does not guarantee that your web pages will be included in the Yahoo! Search index.