There are many ways to get Google to pick up your RSS feed.
1) Link to it from your XML Sitemap and your regular HTML sitemap
2) Ping your RSS feed to a number of aggregators (Technorati the best)
3) Tag your blog posts at social bookmarking services (del.icio.us, wink, etc.)
3) Put LINK-REL mark-up into your blog pages themselves:
<link rel="alternate" type="application/rss+xml" title="Jon Doe’s Blog Feed" href="http://doe.com/feed.xml" />
Google will find it in the end, don't worry.
Good to also provide ways for users to easily subscribe to your RSS feed (addthis.com has some good buttons and RSS email subscribe at feedburner.com also handy).
Check out my syndication page at
SEO Expert Services - Syndicating the SEO Expert Blog Feed
D.