Ask.com, Google, Microsoft Live Search and Yahoo! Jointly announced auto discovery of sitemaps today. This is accomplished by placing the URL of the sitemap within the robots.txt file. The format is as follows: 

Sitemap: PATH-TO-SITEMAP-FILE 

Replace PATH-TO-SITEMAP-FILE with the URL of the sitemap. The sitemap must be on the domain for the pages listed within and you may link to multiple sitemaps.

 Here is the correct format with a live URL: 

Sitemap: http://www.4yourDate.com/sitemap.xml 

If you need to see a working example you can take a look at one of my robots.txt files at http://www.4yourDate.com/robots.txt 

This will greatly decrease the amount of management effort involved in maintaining and submitting a sitemap. Ask also announced the attention of a sitemap submission URL at http://submissions.ask.com/ping?sitemap=SiteMapURL

Replace SiteMapURL with the URL to your sitemap, i.e. http://submissions.ask.com/ping?sitemap=http://GottaBreakUp.com/sitemap.xml 

If you have not yet created a sitemap for your site there are many free services for small site owners. One that I have found to work very well and highly recommend for sitemap generation is http://www.xml-sitemaps.com They have a nice online system that will allow you to quickly index up to 500 pages with the option of purchasing a stand alone system that you can index an unlimited number of pages. If properly used this should greatly enhance your visibility in these search engines.