The proposal to support the common feed icon has passed 5-0, with RSS Advisory Board members Meg Hourihan, Jenny Levine, Eric Lunt, Randy Charles Morin and myself voting in favor.
In an effort to make the concept of syndication easier for mainstream users, Internet Explorer, Mozilla Firefox, and Opera will all identify RSS and Atom feeds with the same icon:
The board has adopted the symbol on this site and encourages its use on web sites, browsers, and syndication software.
Additionally, the board encourages web publishers to use the icon on any feed, regardless of whether it employs Atom or the two formats that call themselves RSS: RDF Site Summary and Really Simple Syndication.
If you've added the icon to a site published with Movable Type, WordPress or another weblog publishing system, your tips on implementing the icon are welcomed on the RSS-Public mailing list.