After uploading your RSS file to your server, you'll still need to inform people of its existence. When you create a new feed, running through these few steps will debut your feed in style:
Advertise to Web surfers! Put an XML button or text link on your page, linking to the RSS file. This [XML] button is the widely-recognized graphic for RSS feeds, though variants and remixed designs are generally just as recognizable. Go ahead, right-click, Save as...
Advertise to the machines! Most RSS applications (and some search spiders) will automatically determine your feeds' location when you put the following code in the <head> section of your homepage: <link rel="alternate" type="application/rss+xml" title="RSS" href="url/to/rss/file" />
Get listed by the major feed directories! Syndic8.com and News Is Free are two of the biggest collections of RSS feeds. Before advertising yourself to these sites, though, run a final test against an RSS validator. While Web browsers will render many poorly-coded Web pages, RSS parsers can be less forgiving, and require a well-formed XML file to work with.
Of course, there's always more to discover, if you are so inclined. Solid RSS tutorials have been written by Mark Nottingham, Fagan Finder, and Danny Sullivan. We'd be remiss not mentioning WebReference.com's large RSS library, and the surprise entry from the State of Utah which provides a great introduction to the subject. Lastly, of course, there's a definitive dead-tree resource from O'Reilly press, covering RSS in depth, not to mention a special RSS DevCenter site.